JP2013108941A - Optical transmission discriminator and optical transmission body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the conventional optical transmission discriminator in which: detection efficiency of light is significantly improved in comparison with an optical fiber identifier, but an unstable measurement value, an increase in transmission loss, an occurrence of disconnection, degradation of long-term reliability or the like easily occur when applied to a coated optical fiber, an optical fiber cord, an optical fiber cable or the like.SOLUTION: A coating removed part of an optical cord 11 in a state of an optical fiber strand 11a is held freely movably between optical fiber fixing parts 15 by a length according to a curved shape when fitting to a photodetector 30 that separate from an optical leakage component 10 and an optical transmission line and a predetermined extra length, and is held in the optical transmission line by the optical leakage component 10. The optical fiber strand 11a is stably held by forming an optical transmission line curved part when fitting. An optical signal for transmitting the optical transmission line is leaked from the optical transmission line curved part and measured by a light receiving element 59 of the photodetector 30, and discriminates a transmission state. An optical transmission discriminator can be used as an optical fiber identifier for optical fiber cord which is strong against bending, or a simple transmission strength measuring instrument, or an optical transmission surveillance monitor.

Description

  The present invention relates to an optical transmission line used for optical communication, LAN (local area network), optical wiring, etc., whether the optical signal propagates through the optical transmission line, the propagating optical signal is normal, or the intensity is stable. It is used to determine the connection state such as whether the optical transmission line is normal, whether the connection of the optical transmission line is normal, or not disconnected, or for the purpose of contrasting the optical transmission line. Light used for transmission light intensity monitoring that easily measures the intensity, and also used as a monitor unit for devices that maintain these functions over the medium to long term and monitor changes in the transmission state of the optical transmission line over the medium to long term The present invention relates to a transmission discriminator and an optical transmission body such as an optical fiber core wire, an optical fiber cord, and an optical fiber cable to which the optical transmission discriminator is applied.

  Conventionally, the importance of optical transmission discriminators that discriminate the transmission status such as the connection status and live status of optical transmission lines during construction of optical lines such as rewiring of optical transmission lines has been pointed out. Devices having such performance have not been widely used. For example, a “cardiac wire contrast device (ID tester)” disclosed in Patent Document 1, Patent Document 2, and the like has been used as a substitute. The “cardiac contrast device” is composed of a light source for core wire contrast and a light detector for core wire contrast, and the discrimination light is inserted into the optical transmission line from the open end of the station building or the like using the light source for core wire contrast, Each optical transmission is detected by leaking a part of the optical signal from the optical fiber by bending the optical fiber cord that constitutes the optical transmission line using the optical detector for detecting the core wire, and detecting the leaked light. It is a device for identifying a path, and is used for a continuity test when an optical transmission path is laid. This "core wire contrast device" only needs to generate a curved portion in the optical transmission medium (optical fiber) only at the time of measurement, so there is no factor that increases the optical transmission loss during the time when the optical transmission path is not compared. There are features.

  When using this optical fiber for detecting a core wire to determine the transmission state of the optical transmission line, such as the connection state and the live line state, the light source for the core wire reference is not used without connecting / disconnecting the transmission line in a station or the like. The determination is made based on the current optical signal while maintaining the connection of the optical transmission line without using it. Also, when determining the transmission state of the working optical transmission line, the transmission state discriminator must not interfere with the transmission of the working light and cause a communication failure. For example, an insertion loss of 1 dB or more will not occur. However, this is an essential condition for measurement.

  However, in the above-mentioned conventional “cardiac wire contrast device” disclosed in Patent Document 1, Patent Document 2, etc., the leakage light caused by the bending of the optical fiber passes through the multilayer coating layers of the optical fiber cord and cables, and absorbs it. However, since the light is diffused over a wide range with scattering, the light detection efficiency is greatly reduced.

  In addition, the increase in optical loss due to bending greatly depends on the wavelength of the optical signal, and in detecting an optical signal with a short wavelength, the optical fiber forming the optical transmission path needs to be largely curved. Therefore, when short-wavelength and long-wavelength optical signals are transmitted at the same time, it is necessary to keep the bending radius of the optical fiber above a certain value in order to suppress insertion loss on the long-wavelength side. However, since the insertion loss at a short wavelength can be further reduced, there is a possibility that the light intensity of the leaked light will be below the detection limit. Conversely, if the radius of curvature of the optical fiber is reduced in order to secure the leakage light intensity at the short wavelength, an even greater insertion loss occurs at the long wavelength, which may cause an obstacle to signal transmission at the long wavelength. It has the disadvantage of becoming larger.

  Since the optical transmission line (live line) in use is not the object to be measured and the optical transmission line that is not being used is the object to be measured in the core line control, the increase in insertion loss in this case is not a problem. Therefore, when the working light is detected by using the optical fiber for detecting the core wire, the optical loss for extracting the working light is large, and it cannot be applied to an optical transmission line in which a large light loss margin (loss margin) cannot be secured. Had the disadvantages. In the cord contrast, since the strength of the contrast control light to be contrasted can be ensured to be much larger than the minimum intensity of the working signal light, there is no problem even when the light loss in the cord contrast is large.

  In addition, it is possible to change the bending condition significantly when detecting a long wavelength signal and when detecting a short wavelength signal, but before detecting the presence or absence of a short wavelength optical signal, It becomes necessary to confirm the long wavelength optical signal. Conversely, even when the long wavelength optical signal is not detected, it is necessary to confirm the presence or absence of the short wavelength optical signal. As a result, the amount of work is greatly increased in any case, so that this method is not practical and is not practically used.

  Conventionally, in addition to the above “core wire contrast device”, the leaked light from the connection portion of the optical fiber core wire is not bent as disclosed in Patent Literature 3 and Non-Patent Literature 1 and the like. There is a device for detecting a heartbeat and performing a cardiac contrast.

  However, since the intensity of the detected optical signal is very small, the conventional apparatus for performing contrast control disclosed in Patent Document 3 is affected by sunlight and other natural noise when detecting leaked light. In order to improve this, the modulated light modulated at a specific frequency is inserted into the optical transmission line, and a part of the modulated light leaking from the fusion splicing part is detected. Therefore, the conventional apparatus for performing contrast control disclosed in Patent Document 3 determines the influence of sunlight or other natural noise when determining whether the current optical signal is propagating through the optical transmission line medium. It has the disadvantage that it is easy to receive and in principle it is difficult to reliably discriminate. In addition, a simple in-line optical power monitor disclosed in Non-Patent Document 1 may be installed in the optical transmission line in advance and used for discriminating the working light. However, this device has a high unit price per optical transmission line. Therefore, it is not popular.

  As described above, the conventional bending method for detecting leaked light by bending the optical fiber core has a drawback in its application range. Expansion of the application range of the equipment is expected.

  Methods that overcome the above drawbacks are disclosed in Patent Documents 4, 5, and 6 and Non-Patent Documents 2 and 3.

  Patent Document 4 and Non-Patent Document 2 disclose a technique that enables transmission discrimination without taking out a wired optical fiber by installing a light leakage component in an optical element part such as an optical termination tray. Has been. In Patent Document 5, as a technique in which a similar configuration is applied to an optical adapter or an optical cord, there is a technique that greatly improves the detection efficiency of leaked light by curving the optical element wire portion with an installed light leak component. It is disclosed. Further, Patent Document 6 and Non-Patent Document 3 expand these techniques, set a light leakage curved surface for the light leakage component, and set an optical transmission line presser for the photodetector, thereby reducing the size and reducing the size. Technologies that have realized price and applied to optical termination trays, optical adapters, optical devices, etc. have been released.

  Patent Document 7 discloses a technique similar to this, in which an optical fiber is bent at the time of measurement inside the optical fiber connector, and live line discrimination and core line comparison are performed based on the bending loss. However, this method does not actively control the bending shape at the time of measurement, and the relative position of the light receiving element is not optimally set. It has disadvantages such as large inefficiency and unstable measurement values, and its practicality is low.

  From these situations, the techniques disclosed in Patent Documents 4, 5, and 6 are one of the most practical techniques as an optical transmission discriminator that discriminates the state of an optical signal transmitted through an optical transmission line such as live line discrimination. It is judged that it is one.

  However, Patent Document 4 (Non-Patent Document 2) and Patent Document 6 (Non-Patent Document 3) disclose the structure of an optical termination tray, an optical termination unit, and an optical termination device. Is a technique applied in a tray-like optical fiber storage section, and does not disclose a technique applied to optical cords. Patent Document 5 discloses a configuration in which the same technology is applied to optical adapters and optical cords, but the basic configuration is the same as that in Patent Document 4, and optimization of the structure for application to these is disclosed. Therefore, when this technology is applied to optical cords, the fitting structure is not stable, and the curved shape is not stable during measurement. Therefore, the reproducibility of measured values is poor and the stability is poor. . In addition, bending stress and tensile stress are applied to the optical fiber during use, which tends to cause an increase in transmission loss and disconnection, resulting in poor long-term reliability. Due to these disadvantages, practicality and commerciality were poor.

  In addition, it can be inferred from the fact that the fitting structure was not stable in the previous proposals. However, these techniques can be used to easily measure the signal light intensity of the optical transmission line without switching the wiring. Examples of application to simple measuring instruments and examples of application as a medium- to long-term optical monitor for monitoring changes in optical signals transmitted through optical transmission lines, with the aim of determining the soundness of optical transmission lines in actual use. There was no.

  In addition, with the recent development of FTTH (Fiber to the Home), many optical fibers have been installed at the end of public lines at homes and offices. The use of an optical fiber that is as easy to use as is widely desired.

  In response to such market demands, bending-resistant optical fiber cords with improved handleability are being introduced. In such an optical fiber cord, an optical fiber having better bending characteristics than a conventional optical fiber is used.

  The conventional optical fiber is ITU-T G.264. An optical fiber based on the 652 recommendation (Non-Patent Document 4) is a standard optical fiber, and the minimum allowable bending radius is 30 mm as a standard. Therefore, in recent years, ITU-TG 657. Introduction of an optical fiber that is compliant with the A1 recommendation (Non-Patent Document 5) and that is resistant to bending with a standard value of the minimum allowable bending radius of 10 mm is in progress. In the future, ITU-T G. 657. An optical fiber having a minimum allowable bending radius standard value of 5 mm based on the B3 recommendation (Non-patent Document 5) has been developed, and it is currently desired to introduce an optical fiber cord using the optical fiber.

  However, as described above, in the conventional optical fiber contrast device, the leaked light caused by the bending of the optical fiber passes through the multilayer coating layers of the optical fiber cord and cables, and spreads over a wide range with absorption and scattering. For this reason, there is a drawback that the light detection efficiency is greatly reduced, and further, the increase in light loss due to the curvature greatly depends on the wavelength of the optical signal.

  Such a conventional optical fiber contrast device is an ITU-T G.264 standard optical fiber. It has been developed for optical cords using optical fibers conforming to the 652 recommendation, and has been widely used because it has various drawbacks, but enables easy control of the cords.

  This conventional cord contrast device has been improved for application to the above-mentioned bending-resistant optical fiber cord, and by optimizing the structure, the ITU-T G.D. 657. It has become possible to apply to an optical fiber core using an optical fiber complying with the A1 recommendation. (Non-patent document 6)

  However, ITU-T G. 657. The improvement applied to the optical fiber cord using the optical fiber conforming to the B3 recommendation can be contrasted with only the optical fiber, but the optical fiber cord has a very poor detection efficiency of the optical signal. The detection limit depends on the reference light intensity, the transmission distance of the reference light, the type of the optical fiber cord, and the like, and is judged to have low certainty. This is presumably because the conventional cord contrast device has an application limit in principle.

JP-A-6-221958 JP 2004-325310 A JP 2005-94720 A JP 2007-85934 A JP 2009-257833 A JP 2009-257834 A JP 2008-33195 A

Mohammad Third Khan, Shinichiro Asada, Ken Takahashi, Jun Yokoyama, “Inline Optical Power Monitor”, 2004 IEICE Electronics Society Conference, C-3-23 p155. Iwasaki, Sakuraba, Mazama, Takeuchi, "Proposal of a separable core wire state discriminator", 2006 IEICE General Conference B-10-2 Iwasaki, Kaniwa, Mazama, Takeuchi, “Evaluation of practicality of separable core wire state discriminator”, 2008 IEICE General Conference B-10-1 ITU-T G. 652 recommendation ITU-T G. 657 recommendation Fujikura Technique No.117 2009 Vol.2 p.16.

  As is clear from Non-Patent Documents 2 and 3, among the techniques of Patent Documents 4 to 6, a specific structure is disclosed in a wiring tray in a closure using an optical fiber core wire. It was limited when applied.

  Therefore, when the technology for wiring trays of Patent Documents 4 to 6 is applied to an optical fiber core, an optical fiber cord, an optical fiber cable, etc., unstable measurement values, increase in transmission loss, occurrence of disconnection, long-term There was a drawback that reliability was easily lowered.

  We apply the techniques disclosed in Patent Documents 4 to 6 to optical fiber cores, optical fiber cords, optical fiber cables, etc., clarify these defects experimentally, and prove the requirements for practical use, The present invention has been devised.

  In addition, a transmission light intensity monitor that can easily measure the signal light intensity of the optical transmission line without switching wiring, without mounting relatively expensive optical components that cause an increase in transmission loss during non-measurement. Until now, there has been no medium- to long-term optical monitor for monitoring changes in the optical signal transmitted through the optical transmission line in use.

  Also, the conventional cord contrast device is an ITU-TG. 657. When applied to an optical fiber cord using an optical fiber that complies with the B3 recommendation, it has a drawback of poor reliability, and the emergence of a core contrast device based on a new principle has been desired.

The present invention has been made to solve such problems,
A light leakage component that is installed in the optical transmission line and holds the coating removal portion of the optical transmission line that is in one of the state of the optical fiber or the optical fiber, and is separate from the optical transmission line, A light detector having a holding structure for storing and holding a light leakage component at the time of measurement, fitting with a part thereof, and stably holding the fitting state,
The photodetector has a light receiving element that measures a transmission optical signal that leaks from an optical transmission path curved portion formed by curving a part of the coating removal portion in the light leakage component only at the time of fitting,
A curve forming portion that is provided in any one of the light leakage component and the light detector and forms a curve shape of the light transmission path curve portion when fitted,
Provided in any one of the light leakage component and the photodetector, and includes an optical fiber presser that presses the curved optical transmission path against the curved forming portion during fitting, and curves along the curved shape of the curved forming portion,
The coating removal portion is fixed to a pair of optical fiber fixing portions whose both ends are configured on both sides in the length direction of the light leakage component, and has a predetermined extra length between the pair of optical fiber fixing portions. Now it is held freely,
The light leakage component guides the coating removal portion from the optical transmission line bending portion to the optical fiber fixing portion between the portion corresponding to the optical transmission path bending portion formed by the bending forming portion and the optical fiber fixing portions on both sides thereof. An optical transmission discriminator for discriminating the transmission state of an optical signal propagating in an optical transmission path, characterized by comprising an optical fiber processing region.

  According to this configuration, the coating removal portion of the optical transmission line that is in either the optical fiber strand or the optical fiber core is held in the optical transmission path by the light leakage component. The coating removal portion held by the light leakage component is bent along the curved shape of the bending portion by being pressed against the bending portion by the optical fiber presser at the time of determining the transmission state of the optical signal. Forming part. An optical signal propagating through the optical transmission line leaks from the transmission line curved portion, and the leaked optical signal is measured by a light receiving element provided in a photodetector separate from the optical transmission line.

  For this reason, since the measurement of the leaked light is performed on the optical signal leaking from the coating removal portion of the optical transmission line that is in either the optical fiber strand or the optical fiber core wire, Patent Document 1 or It is possible to significantly improve and stabilize the light detection efficiency as compared with the case where the conventional optical fiber for contrast detection disclosed in Patent Document 2 is simply used.

  In addition, the optical transmission path covering removal part in the light leakage part is fixed freely at both ends in an open state with a predetermined pre-length between the pair of optical fiber fixing parts, and the optical transmission line bending part is a curved forming part. By providing an optical fiber processing area between the location formed by the optical fiber and the optical fiber fixing parts on both sides, unnecessary tensile stress, compressive stress, and local bending occur at the coating removal part when determining the transmission state. A stable state is ensured. In addition, it is possible to secure a larger radius than the fixed radius of the coating removal portion when the transmission state is not determined, and it is possible to stably prevent the occurrence of an increase in light loss that depends on the curvature when not determined, A state that does not cause local bending is stably ensured.

  Usually, the optical fiber is not fixed inside the optical fiber connector. This is because, due to a slight difference in the position of the ferrule in the optical fiber connector between when the optical fiber connector is connected and when it is opened, compressive strain is applied to the optical fiber core wire, causing local bending, resulting in loss of optical loss. This is to avoid an increase factor. In the initial light leakage component according to the present invention, the optical fiber connector was prototyped without fixing the optical fiber in the same manner as in the optical fiber connector. It has been found that this causes bending of the optical fiber. Therefore, when an attempt was made to fix the optical fiber at the optical fiber fixing portions on both sides inside the light leakage component, the occurrence of bending of the optical fiber was fundamentally suppressed. This has led to the proposal of a new configuration of the optical transmission discriminator of the present invention.

  As a result, in order to apply the techniques disclosed in Patent Documents 4 to 6 to optical fiber cores, optical fiber cords, optical fiber cables, and the like, new details such as optical fiber cores, optical fiber cords, optical fiber cables, etc. A new holding structure, a new structure that generates leakage light only when determining the optical transmission state, and a non-discrimination that does not cause an increase in optical loss, a new structure that is required for the photodetector to stabilize the detection light, In addition, an optical transmission discriminator having a structure with excellent long-term reliability is provided.

  Therefore, the conventional defect, which is poor in reproducibility of measured values and inferior in stability, is improved. Further, an increase in transmission loss and disconnection due to tensile stress, bending, etc. are overcome, and excellent long-term reliability.

  Further, the present invention is characterized in that the curve forming portion is provided in the light leakage component, and the optical fiber retainer is provided in the photodetector.

  According to this configuration, the bend forming portion is provided in the light leaking component, so that the coating removal portion of the optical transmission path is stably held by the light leaking component together with the bend forming portion. For this reason, it is possible to stably bend the optical transmission line bending portion along the curve forming portion when determining the transmission state, and it is possible to stabilize the insertion loss characteristic and the optical signal reception efficiency with good reproducibility. Become. In addition, since the optical fiber retainer is provided in the photodetector, it is possible to reduce the size and price of the optical transmission discriminator and to provide an optical transmission discriminator excellent in operability.

  Further, the present invention is characterized in that the optical detector is provided with a curve forming portion and an optical fiber presser.

  According to this configuration, the coating removal portion held by the light leakage component is turned into the curved formation portion similarly provided in the photodetector by the optical fiber presser provided in the photodetector when determining the transmission state of the optical signal. By being pressed down, it is bent along the curve shape of the curve forming portion. Then, the optical signal leaked from the curved covering removal portion is used for optical transmission discrimination.

  As described above, since both the curved forming portion and the optical fiber retainer are provided in the photodetector, the structure of the light leakage component installed in the optical transmission path of the optical transmission system is simplified, and precise processing accuracy is required. It will not be done. For this reason, it is possible to further reduce the price while maintaining the performance of the optical transmission discriminator. In addition, by providing a light leakage component that holds the coating removal portion of the light transmission path in the light transmission path in advance, the light detector can be installed in the photodetector without replacing the light leakage component already installed in the light transmission system. By exchanging the provided curve forming portion, the curve shape of the curve forming portion can be changed, and the insertion loss, optical signal reception efficiency, and the like of the optical transmission discriminator can be changed as appropriate. In addition, when the optical transmission discriminator is applied to an optical monitor that monitors the medium to long-term stability of the optical transmission path, it is possible to flexibly cope with different required specifications.

  In the present invention, the length of the sheath removing portion is set to a length determined by the curved shape at the time of fitting between the light leakage component and the photodetector, and has a surplus length determined thereby. It is characterized by being held freely between the fiber fixing portions.

  According to this configuration, since the pre-length of the coating removal unit is set to an optimum value, the coating removal unit is appropriately held and fixed freely and freely between the optical fiber fixing units, so that the coating removal unit can be used when determining the transmission state. It is basically guaranteed that no tensile stress or compressive stress is generated. Further, since the extra length is determined to be the minimum necessary length, the occurrence of loss caused by bending or the like when the transmission state is not determined is effectively suppressed.

  Moreover, this invention is characterized by the curvature radius of a curve formation part being 1.5 mm or more and 5.5 mm or less.

  According to this configuration, it is possible to minimize the wavelength dependence of the insertion loss generated in the transmission line bending portion without causing physical damage to the transmission line bending portion due to bending during measurement. At the same time, the detection limit of the signal light intensity at the wavelength of 1.31 μm can be made −40 dB or less while suppressing the insertion loss at 55 μm to 0.5 dB or less.

  FIG. 1 shows one of the investigation results that led to the present invention. When the optical fiber is bent with a certain radius of curvature, the relative loss at the wavelength of 1.31 μm is obtained with reference to the bending loss at the wavelength of 1.55 μm. It is the experimental result which measured the curvature radius dependence of typical bending loss. In general, the bending loss at the wavelength of 1.31 μm is significantly smaller than the value at the wavelength of 1.55 μm, and the smaller the radius of curvature, the closer the insertion loss at the wavelength of 1.31 μm is closer to the insertion loss at the wavelength of 1.55 μm. The value is shown.

  Here, it is assumed that the upper limit value that does not cause an abnormality in the optical transmission of the insertion loss at the wavelength of 1.55 μm is 0.5 dB, and the optical intensity of the optical transmission of −40 dBm is increased to −80 dBm using a high sensitivity light receiving element. If it can be detected, the best value of the detection efficiency is about −14 dB, so the minimum value of the bending loss at the required wavelength of 1.31 μm is about 0.01 dB. By using this value and inferring from the survey results of FIG. 1, it is determined that the radius of curvature due to bending needs to be 5.5 mm or less. Further, the lower limit of the radius of curvature of the curved portion is mainly defined in a range that does not physically damage the optical fiber core, and the radius of 1.5 mm is estimated to be almost the limit.

  Since the radius of curvature of curvature in a normally used cord contrast device is about 10 mm, even if judging from this result alone, there is a limit to the measurement limit when using a common cord contrast device for distinguishing live lines. Yes, determined to be impractical.

  Further, according to the present invention, the optical fiber processing region is formed continuously with the curve forming portion, and the coating removal portion is bent opposite to the bending direction of the curve forming portion when fitted, and the optical fiber folded region. Formed between the area and the optical fiber fixing part, the coating removal part held by the optical fiber fixing part at the time of fitting is held in a straight line without bending from the optical fiber fixing part, and the coating is removed at the time of non-fitting. An optical fiber alignment region having a predetermined length is provided in which the portion becomes a part of a space forming a curved structure.

  According to this configuration, the coating removal portion between the pair of optical fiber fixing portions at the time of transmission state determination is forcibly deformed into a shape along the curved shape of the curved forming portion by the curved forming portion and the optical fiber presser, Each coating removal portion in each optical fiber alignment region is held in a state close to a straight line. On the other hand, the sheath removal part between the pair of optical fiber fixing parts at the time of transmission state non-discrimination is released from those stresses, and both ends are fixed in a state having a predetermined pre-length, so that it is curved with a specific curvature. Is kept. At this time, the curvature of curvature is sufficiently larger than the curvature of curvature at the bend forming portion and the optical fiber folding region due to the contribution of the coating removal portion in the optical fiber alignment region. If the optical fiber alignment region is not provided, the specific radius of curvature at which the coating removal portion is curved and held is the radius of curvature of the optical transmission line bending portion at the time of measurement and the coating at the optical fiber folding region. This indicates an intermediate value of the radius of curvature of the removal portion. In order to increase the radius of curvature and prevent deterioration of long-term reliability of the coating removal portion in the curved state, it is necessary to set an optical fiber alignment region.

  Therefore, the optical fiber alignment region exhibits an effect of stably preventing an optical signal insertion loss due to excessive bending of the coating removal portion in the light leakage component when the transmission state is not determined.

  Further, according to the present invention, the center angle of the arc formed by the optical transmission line bending portion at the time of fitting is equal to the sum of the center angles of the arcs formed by the coating removal portions of the optical fiber folded regions on both sides at the time of fitting. It is characterized by that.

  According to this configuration, between the pair of optical fiber fixing parts in the light leakage component at the time of transmission state determination, the sheath removal part has the central angle of the arc of the optical transmission line curved part formed in the center by the curved formation part. The optical transmission line bending portion is bent by being equal to the sum of the central angles of the arcs of the bending portions formed equally by the optical fiber folded region on both sides. For this reason, in the light leakage component at the time of determining the transmission state, the coating removal portions in the vicinity of the optical fiber fixing portions on both outer sides of the curved portions in the optical fiber folded region are held in a straight line. Accordingly, when the transmission state is determined, no additional bending stress is applied to the coating removal portion near the optical fiber fixing portion, so that an extra increase in optical loss and a physical deterioration factor of the optical transmission path do not occur.

  In addition, the present invention provides a long-term reliability of the optical fiber or the optical fiber core wire that forms the coating removal portion because the curvature of curvature when the coating removal portion is not fitted between the optical fiber fixing portions that are freely fixed is fixed. The width of the optical fiber alignment region is converted from the curvature and set.

  According to this structure, the long-term reliability of the coating removal part at the time of non-measurement is ensured. The optical fiber used for the optical transmission line has a minimum value of the radius of curvature when it is always maintained from the viewpoint of long-term reliability. For example, a conventional standard single-mode optical fiber In some cases, it is 30 mm, and in the case of an optical fiber that is resistant to bending used in FTTH or the like, it is 15 mm. Therefore, even in the light leakage component of the transmission path discriminator according to the present invention, it is necessary that the coating removal portion at the time of non-measurement keeps the values according to these specifications. However, since these values depend on the type of optical fiber and the like, the minimum radius of curvature is not limited to these values.

  Further, according to the present invention, in the optical fiber retainer, an optical fiber holding gap portion is formed as a predetermined light passing member portion or a gap through which an optical signal passes in a region fitted with the curve forming portion, and each optical fiber folding region It has the structure which fits at least one part of this.

  According to this configuration, when determining the transmission state, the coating removing unit is bent along the curved shape by the bending unit by fitting the optical fiber retainer with at least a part of each optical fiber folded region, An optical insertion loss according to the design is generated, and a part of the optical signal is radiated to the outside of the optical transmission line. At this time, an optical fiber holding gap portion is formed as a predetermined light passing member portion or gap through which an optical signal passes in a region where the optical fiber holding portion is fitted with the bending forming portion, and light leaks from the optical transmission path bending portion. Since the signal is not blocked, the optical signal radiated from the coating removal portion that contacts the curve forming portion to the outside of the optical transmission path is efficiently measured by the light receiving element of the photodetector without being blocked by the optical fiber holding portion. The

  At that time, the optical fiber retainer is fitted to at least a part of each optical fiber folded region, so that the optical fiber retainer deforms the optical fiber in the curved portion and the entire optical fiber folded region along these shapes. Therefore, it is possible to form the optical transmission line curved portion while preventing an increase in transmission loss of the optical fiber in a region other than the curved forming portion. Therefore, the optical fiber retainer does not necessarily need to directly press the optical transmission line bending portion, but it is fitted to at least a part of the optical fiber folding region, and the curved shape of the optical fiber folding region of the optical transmission line bending portion and the coating removal portion Can be formed efficiently.

  Further, the present invention is characterized in that the radius of curvature of the curved surface in contact with the coating removal portion is 1.3 times or more than the radius of curvature of the curve forming portion at the portion that fits with the optical fiber retainer in the optical fiber folded region. And

  According to this configuration, it is possible to minimize the occurrence of optical loss due to bending of the coating removal portion in the optical fiber folding region when determining the transmission state, and minimize the influence on the optical transmission state. Is possible.

  For example, FIG. 2 is one of experimental results that led to the present invention, and is an experimental result of measuring the curvature radius dependence of a bending loss measured at a wavelength of 1.55 μm using a single-mode optical fiber. Yes, the bending loss increased exponentially as the radius of curvature decreased. Here, the central angle of bending is constant. Referring to the figure, when it is assumed that the bending radius of curvature of the optical transmission line bending portion is 5.5 mm and the bending loss generated at that time is 0.5 dB, the curvature radius of the coating removal portion bending in the optical fiber folded region is It can be seen that if it is set to 1.3 times or more, 7.15 mm or more, it is possible to suppress the bending loss generated at the coating removal portion in the optical fiber folded region to 0.1 dB or less. It is judged that it is indispensable practically to suppress the loss generated in the coating removal portion other than the transmission path curved portion to 0.1 dB or less.

  Further, according to the present invention, in the optical fiber folded region, optical fiber folded portions that are curved opposite to the bending direction of the curved forming portion and have a curved surface continuous to the curved forming portion are formed on both sides of the curved forming portion. The optical fiber turn-back portion is fitted to face the optical fiber presser when fitted, and a part of the coating removal portion is stably held between them.

  According to this configuration, the coating removal portion of the optical transmission line at the time of determining the transmission state is opposite to the direction in which the optical fiber folding portion and the optical fiber presser are opposed to each other and bent by the bending portion. It is bent and bent, and its shape is stably held, so that the position of the coating removal part in the light leakage component is stabilized, and bending occurs locally at the coating removal part between the optical fiber fixing parts. It becomes possible to suppress this, and the curved shape of the coating removal portion is stabilized in the long term.

  Further, the present invention provides a groove having an effective depth within the outer diameter of the sheath removing portion within ± 0.1 mm, an effective width greater than or equal to the outer diameter of the sheath removing portion, and less than or equal to the width of the light receiving surface of the light receiving element. It is characterized in that it is formed in the length direction of the optical transmission line at at least one position of the optical fiber presser or the optical fiber folded portion.

  Here, the effective depth means the depth itself when the cross section of the groove is rectangular, but in the case of a V groove having a V-shaped cross section, the effective depth is fitted on the part surface without the V groove and in the V groove. This represents the difference in the position of the coating removal portion in the groove depth direction from the case. Similarly, the effective width of the groove represents the groove width itself when the cross section of the groove is rectangular, but in the case of other shapes, the effective width of the groove is determined from the distance that the sheath removal part can move in the groove width direction in the groove. Calculated. For example, in the case of a V-groove, since the coating removal portion cannot move in the groove width direction, it is considered that the effective groove width is equal to the width of the coating removal portion.

  According to this configuration, the covering removal portion between the pair of optical fiber fixing portions at the time of determining the transmission state is formed in the length direction of the optical transmission path in at least one place of the curve forming portion, the optical fiber holding portion, or the optical fiber folding portion. The grooves are aligned in the length direction of the optical transmission line without applying stress from the side surface to the optical fiber of the coating removal portion and without increasing the distance between the optical fiber and the light receiving element. For this reason, it becomes possible to stabilize the position of the optical fiber in the vicinity of the bending portion formed in the coating removal portion when determining the transmission state, and it is possible to prevent the light receiving efficiency from being lowered due to a positional factor, and to bend the coating removal portion. It is possible to stably improve the optical coupling degree between the light receiving element and the light receiving element.

  Further, the present invention is characterized in that the cross-sectional shape of the groove is basically a V-groove having a symmetrical shape, and a light reflection surface is formed on at least a part of the groove inner surface.

  Here, the basic shape of the V groove is a V groove, but it is not strictly necessary to be a V groove. For example, the shape of the bottom portion of the V groove may be somewhat free and flat. Moreover, it shows that both ends may be gently curved.

  According to this configuration, not only the leaked light emitted from the surface of the optical fiber facing the light receiving element of the detection unit, but also the leaked light emitted from the surface of the optical fiber in a direction perpendicular to the optical fiber surface efficiently enters the light receiving element. Therefore, not only does the light detection efficiency increase significantly, but the polarization dependency of the light detection efficiency is greatly eliminated, and reproducibility is not dependent on the polarization state of the optical signal transmitted through the optical fiber. In addition, it is possible to obtain light detection characteristics with excellent stability.

  Further, the present invention is characterized in that the shortest distance between the surface of the light transmission path bending portion bent along the bending shape of the bending forming portion and the light receiving surface of the light receiving element during fitting is 2 mm or less. .

  According to this configuration, the distance between the light transmission path curved portion of the coating removal unit and the light receiving element during transmission state determination is minimized, and the distance between the light transmission path curved portion of the coating removal unit and the light receiving element is reduced. It is possible to improve the degree of optical coupling.

  Further, according to the present invention, the optical fiber retainer is formed with a light reflecting surface that reflects an optical signal to the light receiving element side on at least a part of the side surface of the light passing member portion or the optical fiber retainer gap portion on the optical fiber return region side. It is characterized by being.

  According to this configuration, the optical coupling degree between the light transmission path bending portion of the coating removal portion and the light receiving element is several dB or more, compared to the case where the light reflection treatment is not performed on the side surface of the optical fiber holding side of the optical fiber folding region. It becomes possible to improve.

  Since the leaked light generated at the curved portion of the optical transmission path is divergently emitted outside the optical fiber, the ratio of the leaked light that is directly sensed by the light receiving element is small, and the main factor that decreases the optical coupling degree is the leaked light. It is a divergence. Therefore, as a means for compensating for this, a light reflecting surface for reflecting an optical signal to the light receiving element side is formed on at least a part of the side surface of the optical fiber holding gap side portion of the optical fiber holding member or the optical fiber holding gap portion. It is very effective to improve the optical coupling degree. Further, since the optimum positions for condensing are different from each other depending on the propagation direction of the optical signal light, this reflection means becomes more effective when one light receiving element is installed.

  In addition, the present invention is characterized by including an operation mechanism that holds the fitting between the light leakage component and the photodetector when not operated.

  According to this configuration, when the operating mechanism is not operated, the fitting between the light leakage component and the photodetector is held, and the optical transmission line bending portion is added to the coating removing portion by the action of the operating mechanism on the optical fiber presser and the bending forming portion. Is formed and held, leakage light is generated in the curved portion of the optical transmission path, and leakage light is measured.

  For this reason, since the operation mechanism is not operated when the transmission state is determined by forming the optical transmission line bending portion in the coating removal portion by the optical fiber pressing and bending forming portion, the optical fiber pressing and bending formation is caused by the operation. The relative position with respect to the portion does not change, the fitting state between the optical fiber retainer and the curve forming portion is stabilized, and the reproducibility of leakage light measurement is improved. Therefore, the insertion loss of the optical transmission line and the optical coupling degree between the curved part of the optical transmission line and the light receiving element at the time of determining the transmission state are stabilized, and the difference in the measured value of the leaked light caused by human factors is minimized. Is possible. In addition, since the insertion loss and optical signal reception efficiency at the time of determining the transmission state are stable over the long term, an optical transmission discriminator is used as an optical monitor for measuring the medium to long-term stability of the optical signal in the optical transmission path. It becomes possible.

  In the present invention, the photodetector is separated into a detection unit including a light receiving element and a photodetector main body including a control circuit for performing transmission state determination control of an optical signal measured by the light receiving element. Features.

  According to this configuration, the photodetector is separated into the detection unit and the photodetector main body, and the light receiving element that detects the leaked light from the optical transmission path curved portion formed in the coating removal unit is separated from the photodetector main body. By configuring the body detection unit, the detection unit can be significantly reduced in size, and the workability of the optical transmission state determination work is greatly improved. In addition, when an optical transmission discriminator is used as an optical monitor that measures the medium to long-term stability of optical signals in the optical transmission line, the volume of space occupied by the optical transmission discriminator in the vicinity of the optical transmission line is greatly increased. An optical monitor that is reduced and has excellent storage and retention is provided.

  In addition, the present invention is characterized in that the photodetector has a function of converting a measured value into a signal light intensity transmitted through the optical transmission line from an optical coupling efficiency measured in advance.

  According to this configuration, as a practical power checker, it is possible to easily measure the signal light intensity transmitted through the optical transmission line without changing the connection, and display the result on the display unit of the photodetector. It becomes.

  Conventionally, it has been impossible to measure the intensity of signal light transmitted through an optical transmission line with a core wire contrast device or the like. This is because the relevance of the detection light intensity is poor and the relevance of the measurement result is low in the conventional cord contrast device because the reproducibility of the detected light is poor.

  In the technique of the present invention, since the measurement target is limited to the optical fiber strand or the optical fiber core wire, the detection efficiency of the photodetector can be corrected in advance, and the individual difference is greatly reduced.

  Therefore, since the technique of the present invention is excellent in measurement reproducibility and stability, it is possible to measure the intensity of signal light transmitted through the optical transmission line by selecting a measurement wavelength during measurement.

  In addition, when the detection unit is not dependent on the type of optical fiber (elementary wire or core), it is necessary to select the type of optical fiber. However, the selection of this type of optical fiber can be automated. is there.

  Here, the solid difference of the light receiving efficiency of the light receiving element, the solid difference of the electric circuit, etc. is corrected in advance as the solid difference of the photodetector, and the solid difference of the fitting / gripping mechanism of the light leakage component of the photodetector is detected by the photodetector. Is corrected as the detection efficiency.

  The measurement accuracy greatly depends on the processing and assembly accuracy of the light leakage component, but by practically suppressing these individual differences, the signal light intensity transmitted through the optical transmission path can be easily measured without switching. As a power checker, practical performance can be obtained.

  Further, in order to ensure measurement accuracy, it is desirable to appropriately select and limit the characteristics and coating color of the optical fiber used as the optical transmission path for mounting the light leakage component.

  Further, the present invention is characterized in that an identification code indicating a correction value for correcting the individual difference due to the light leakage component having a light coupling efficiency measured in advance is written on the light leakage component.

  According to this configuration, the light leakage components are classified according to their optical characteristics, and the signal light intensity transmitted through the optical transmission line is input to the detector at the time of measurement by inputting an identification code indicating the correction value of the displayed light leakage components. The measurement accuracy can be further improved.

  With this correction value, it is possible to correct individual differences depending on characteristics of optical fibers to be used, coating color differences, and processing / assembly accuracy of light leakage components.

  Therefore, basically, there is no need to limit the characteristics, coating color, coating material, etc. of the optical fiber to be used in order to improve the measurement accuracy.

  Further, the present invention is characterized in that the photodetector has an optical line monitoring function and is held for a medium to long term in a state where the light leakage component is held.

  Here, the optical line monitoring function is at least one of a function for identifying a detected value and its detection time, a function for analyzing these data, and a function for determining normality / abnormality of a detected value by setting a determination reference value. It means having at least one of a function having one or more functions and holding and storing these results and a function of outputting these results.

  According to this configuration, the optical transmission path discriminator can check the soundness such as the stability of the transmission characteristics of the optical transmission path. As a result, it is possible to analyze an unexpected transmission loss abnormality, instantaneous interruption, output stability of the light source in use, etc. almost simultaneously with the occurrence of these situations, and early response is possible.

  The present invention is also characterized by being applied to an optical fiber cord using an optical fiber having an optical fiber having a core line contrast function and a minimum allowable bending radius of 5 mm or less.

  Here, an optical fiber having a minimum allowable bending radius of 5 mm or less is ITU-T G.264. 657. An optical fiber that complies with the B3 recommendation.

  According to this configuration, the optical fiber cord is superior in light detection efficiency at each stage as compared with the conventional core wire contrast device, and therefore, it is difficult for the conventional core wire contrast device. 657. The optical fiber cord using an optical fiber that is strong in bending and has a minimum allowable bending radius of 5 mm or less, such as an optical fiber that complies with the B3 recommendation, can be reliably performed. Furthermore, since the wavelength dependence of detection efficiency is greatly suppressed, low loss core line contrast is possible in almost the entire range of the single mode wavelength range, and at the same time, live line discrimination is also possible. It is possible to prevent accidents that accidentally disconnect the working line.

  By applying the technique of the present invention to the optical fiber cord, we have experimentally confirmed that the optical fiber cord can be controlled with a cord and that it exhibits excellent characteristics, leading to the present invention.

  According to another aspect of the present invention, there is provided an optical transmission body that forms an optical transmission path, wherein at least a part of the optical transmission element is provided with at least a part of the light leakage component described above. .

  According to this configuration, since the optical transmission body includes the light leakage component, the optical transmission determination according to the present invention is possible by arranging the optical transmission body in a necessary place such as a station building or a relay station in advance. Become.

  According to the present invention, the optical transmission discriminating techniques disclosed in Patent Documents 4 to 6 are used to increase transmission loss, occurrence of disconnection, measured values that are inferior in reproducibility, unstable measured values, lower long-term reliability, etc. A specific new configuration for eliminating factors and applying to optical fiber cores, optical fiber cords, optical fiber cables, etc. is disclosed, and efficient optical transmission discrimination technology with excellent performance, workability and reliability is disclosed It becomes possible to apply to.

  Thereby, it is practically possible to determine the optical transmission state in an optical transmission line such as an optical fiber core, an optical fiber cord, and an optical fiber cable without interrupting the optical transmission line instantaneously. In addition, according to the present invention, even in the case of the core line contrast that has been conventionally performed using the core line contrast device, the insertion loss of the optical transmission line is kept low and stable, and higher than the conventional level. It becomes possible to carry out with sensitivity. In particular, ITU-T G.I. 657. With respect to an optical fiber cord using an optical fiber compliant with the B3 recommendation, it is possible to reliably perform the control of the core wire with low loss.

  From these facts, it is possible to introduce an optical transmission discriminator which has not been conventionally used. The introduction cost of the optical transmission state discrimination technology can be reduced. Further, it is possible to easily measure the signal light intensity during transmission at low cost without using an optical device or the like and without switching wiring. Further, it can be applied as an optical monitor for monitoring changes in the medium to long term of the optical transmission line.

The figure showing one of the experimental investigation results which resulted in this invention. Experimental results of measuring the radius-of-curvature dependence of the relative bending loss at a wavelength of 1.31 μm with the bending loss at a wavelength of 1.55 μm as a reference when the optical fiber was bent with a certain radius of curvature. is there. The figure showing one of the experimental investigation results which resulted in this invention. It is the result of having measured the curvature radius dependence of the bending loss in the wavelength of 1.55 micrometers at the time of bending an optical fiber strand with a fixed curvature radius. Here, the central angle of each bend was constant. It is an external view of the light leakage component which comprises the optical transmission discriminator by one Embodiment of this invention. 3A is a cross-sectional view of the light leakage component shown in FIG. 3 cut in the length direction, and FIG. 3B is an upper surface of the light leakage component body observed when the light leakage component is opened with the slide cap removed. FIG. It is a figure showing the curved state of the coating | coated removal part in a light leakage component main body, (a) is the state at the time of measurement, (b) is the state at the time of non-measurement. It is an external appearance block diagram of the photodetector which comprises the optical transmission discriminator by one Embodiment of this invention. (A) is sectional drawing of a detection part at the time of fracture | rupturing the upper case with a lever which comprises the detection part of the photodetector shown in FIG. 6 on a surface horizontal to a case surface, (b) is the housing | casing of a detection part. It is a longitudinal cross-sectional view of the detection part when the detection part outer case and lever upper case which comprise are fractured | ruptured by the surface perpendicular | vertical to a case surface. (A) is a cross-sectional view showing a state in which the light leakage component is inserted and held in the light leakage component holding part of the detection unit shown in FIG. 7, and (b) is an optical fiber of the light leakage component from that state. FIG. 4C is a cross-sectional view illustrating a state in which the optical fiber retainer of the folded portion and the detection unit is fitted, and FIG. FIG. It is a graph which shows the result of having tested the stability of the detection light required when using the optical transmission discriminator by one Embodiment of this invention as an optical monitor.

  Next, an embodiment for implementing the optical transmission discriminator according to the present invention will be described.

  FIG. 3 is an external view of the light leakage component 10 constituting the optical transmission discriminator according to this embodiment.

  The optical cord 11 constitutes an optical transmission body to which the optical transmission discriminator according to the present embodiment is applied, and is an optical cord of a standard single mode optical fiber having an outer diameter of 2 mm and a length of 3 m. An optical fiber connector is attached. The optical transmission discriminator according to the present embodiment discriminates the transmission state of the optical signal propagating in the optical transmission path. At least a part of the optical cord 11 is provided with a light leakage component 10. The light leakage component 10 has a two-stage cylindrical shape, and its outer dimensions (length L × diameter φ) are about 60 × φ6 [mm]. A slide cap 12 is attached to the center of the light leakage component 10, and end tubes 13 are attached to both sides thereof.

  FIG. 4A is a cross-sectional view of the light leakage component 10 cut in the length direction.

  The light leakage component 10 includes a light leakage component main body 14, a slide cap 12, and end tubes 13 on both sides. The light leakage component main body 14 is made of ABS resin and has a rectangular parallelepiped shape, and both end portions covered by the end tube 13 have a semi-cylindrical shape. The light leakage component main body 14 and the end portions of each end tube 13 in a rectangular parallelepiped shape were housed in a slide cap 12 having a hollow cylindrical shape.

  The optical cord 11 inside the light leakage component 10 is not cut and the inner optical fiber 11a is exposed to form a coating removal portion, and both ends of the optical fiber 11a are connected to the cord of the optical cord 11. Along with the end portion of the outer cover 11b and the exposed portion of the secondary covering material 11c and the strength member 11d in the optical cord 11, it was adhesively fixed in the end tube 13 of the optical fiber fixing portion 15 of the light leakage component main body 14 with an adhesive.

  In order to set the length of the optical fiber 11a, which is the sheath removing portion, determined by the curved structure at the time of determining the optical transmission state between the optical fiber fixing portions 15, the predetermined optical transmission using a jig (not shown) Both ends are fixed to a pair of optical fiber fixing parts 15 formed on both sides in the length direction of the light leakage component 10 with a predetermined length determined by the path length and a pair of optical fibers. It is held freely between the fixed portions 15. Here, the extra length is the difference between the length of the optical fiber 11 a stretched between the pair of optical fiber fixing portions 15 and the distance between the pair of optical fiber fixing portions 15.

  The light leakage component main body 14 of the light leakage component 10 is formed with a curve forming portion 17 on the upper surface of the central portion, and the light transmission path bending portion of the optical fiber 11 a that leaks the optical signal is formed by the curve forming portion 17. An optical fiber processing region 18 for guiding the optical fiber 11a from the curved portion to the optical fiber fixing portion 15 is provided between the place where the optical fiber is fixed and the optical fiber fixing portions 15 on both sides thereof. The bend forming portion 17 has a bend shape having a curvature with which the optical fiber 11a forms a bend portion of the transmission path when determining the optical transmission state. The lateral width is larger than the outer diameter of the optical fiber 11a, and slopes 23 for guiding the optical fiber to the curve forming portion 17 are formed obliquely on both side surfaces of the curve forming portion 17 (FIG. 4 ( b)). Further, the optical fiber processing region 18 aligns the optical fiber strands 11 a on both sides of the bending portion 17, and smoothly introduces the optical fiber strand 11 a into the optical cord 11 fixed to the optical fiber fixing portion 15. It has become a space.

  The optical fiber processing region 18 includes an optical fiber turning region for introducing the optical fiber 11a bent by the bending forming unit 17 into the optical fiber fixing unit 15 at the time of determining the optical transmission state, and light at the time of determining the optical transmission state. The optical fiber return region includes an optical fiber return region 19 and an optical fiber alignment region for suppressing the occurrence of bending loss of the optical fiber 11a outside the optical fiber return region. A flat portion 20 is formed in the optical fiber alignment region. The optical fiber folded portion 19 has a curved surface that is curved opposite to the curved direction of the curved forming portion 17 on both sides in the length direction of the curved forming portion 17, and continues to the curved forming portion 17. Is formed. The flat portion 20 is a light leakage component that is continuous with the optical fiber return portion 19 in the optical fiber alignment region between the space on the optical fiber return portion 19 and the optical fiber fixing portion 15 outside the optical fiber return portion 19. The main body 14 is formed with a predetermined length. In addition, a concave portion 21 is formed at the center bottom portion of the light leakage component main body 14, and is used for positioning when fitting with a detection portion 31 constituting a photodetector 30 described later when determining the light transmission state.

FIG. 5 is a diagram illustrating a curved state of the optical fiber 11 a between the optical fiber fixing portions 15. FIG. 5A shows the state of the optical fiber 11a when fitted, and FIG. 5B shows the state when not fitted. From FIG. 5A, since the optical fiber 11a at the time of fitting is bent along the bending portion 17 and the optical fiber turn-back portion 19, the length of the optical fiber 11a between the optical fiber fixing portions 15 is shown. The length (L) is longer than the distance (W) between the optical fiber fixing portions, and it can be seen that the pre-length is generated. The length (w) is w = L−W
The value calculated by. Therefore, the length of the optical fiber 11a serving as the coating removal portion is set to a length (L) determined by the curved shape at the time of fitting, and has a pre-length (w) determined thereby. Thus, it can be seen that the optical fiber fixing portion 15 is held freely.

  As shown in FIG. 5A, the sectoral curvature radius R of the bending portion 17 that causes light leakage to the optical fiber 11a when determining the optical transmission state is 4.5 mm, and the sectoral curvature radius of the optical fiber folded portion 19 r was set to 9 mm. The optical fiber 11a is temporarily held and fixed along the curve forming portion 17, the optical fiber folded portion 19 and the flat portion 20 when determining the optical transmission state. The radius of curvature r of the curved surface is 1.3 times or more the radius of curvature R of the curved surface of the curved forming portion 17. In this embodiment, the radius of curvature r of the optical fiber folded portion 19 is 2 of the radius of curvature R of the curved forming portion 17. Since it is twice (r = 2R), it is possible to suppress an effective increase in optical loss due to an optical signal leaking at the optical fiber turn-back portion 19 during measurement.

  Further, as shown in FIG. 5, the fan-shaped central angle θ of the optical fiber folded portion 19 is equal on both sides, and the sum thereof coincides with the fan-shaped central angle β of the curve forming portion 17 (β = 2θ). Designed. That is, in the curve forming portion 17, the center angle β of the arc formed by the optical transmission line curve portion is equal to the sum 2θ of the center angles of the arc formed by the coating removal portions of the optical fiber folded portions 19. Thereby, the optical fiber strands 11a outside the optical fiber folded portion 19 at the time of measurement are held in a straight line with each other, and are guided to the optical fiber fixing portion 15 without being bent in principle.

  Further, as shown in FIG. 5B, the optical fiber 11a at the time of non-fitting is held in a curved state with a constant curvature radius as a whole including the optical fiber alignment region. Here, the width of the optical fiber alignment region is set to a value calculated from the curved shape. Here, the optical fiber 11a needs to be held in a curved state in a range that does not deteriorate the long-term reliability. Generally, this radius of curvature is 15 mm or 30 mm or more.

  In the present embodiment, the optical fiber 11a is slightly lifted from the curved forming portion 17 and the optical fiber folded portion 19 due to the effect of the flat portion 20 as the optical fiber alignment region when not fitted, and The state where the light leakage component main body 14 does not protrude in the height direction is maintained. In this state, the entire optical fiber 11a is held with a curvature radius (Ro) of 15 mm as shown in FIG. 5B, and long-term reliability is ensured. This is produced as an effect of forming the flat portion 20 as the optical fiber alignment region. This radius of curvature is a standard value for ensuring long-term reliability of the used optical fiber.

  Therefore, at the time of non-fitting, the optical fiber 11a between the optical fiber fixing portions 15 is held with a curvature that is 1.5 times or more larger than the curvature of the optical fiber folded portion 19, so that no optical loss occurs and the same light It is held at a curvature defined by the long-term reliability of the fiber strand 11a, and the width of the optical fiber alignment region is converted from the curvature and set.

  When the slide cap 12 is fitted to determine the light transmission state, the slide cap 12 is slid and removed in the length direction of the light leaking component main body 14, and the curve forming portion 17 and the optical fiber processing region 18 of the light leaking component main body 14 are exposed. It becomes a state. FIG. 4B is a top view of the light leakage component main body 14 when the slide cap 12 is opened by sliding, and the slide cap 12 is omitted. As shown in the drawing, the optical fiber 11a is fitted in a straight line in the insertion grooves 24 formed in the optical fiber alignment regions on both sides of the light leakage component main body 14. A wide opening 22 is formed between the optical fiber alignment regions on both sides of the light leakage component main body 14 (here, between the insertion grooves 24 on both sides). In the space corresponding to the optical fiber turn-back portion 19 of the opening 22, an optical fiber retainer 58 of the detection portion 31 constituting the photodetector 30 described later is inserted and fitted when determining the optical transmission state, and at the same time, curved. The light receiving element 59 of the detection unit 31 is close to the space corresponding to the formation unit 17 and is used for measurement. On each side wall of the light leakage component main body 14 at the center of the opening 22, a pair of inclined surfaces 23 are formed as opposing inclined surfaces that are inclined downward toward the central optical fiber 11 a.

  FIG. 6 is an external configuration diagram of the photodetector 30 constituting the optical transmission discriminator according to the present embodiment.

  The photodetector 30 is configured to be separated into a detection unit 31 and a photodetector main body 32 and is connected to each other by a coaxial cable 33. The light detector main body 32 functions as an optical power meter if a light receiving unit (not shown) is mounted instead of the light detecting unit 31 instead of the light detecting unit 31, for example, an optical fiber with an optical connector is attached to the light receiving unit. It is possible to connect and measure the power of an optical signal transmitted through the optical fiber.

  The detection unit 31 has an outer dimension (length L × width D × height H) of about 60 × 35 × 20 mm, and the housing is composed of a detection unit outer case 34 and an upper case 35 with a lever. The upper case 35 with a lever having the lever 35a is provided with a detection unit display unit 36 that displays at least the presence or absence of an optical signal propagating through the optical transmission line. The detection unit display unit 36 includes three LEDs (light emitting diodes), and displays any one of three signal states of no signal, control light, and communication light as a detection result, depending on their lighting state. No signal indicates that no optical signal was detected in the optical transmission line, the reference light was detected in the optical transmission line for the control of the transmission line, and the communication light was communicated to the optical transmission line. This means that the communication light propagating for the purpose is detected.

  The photodetector main body 32 has an external dimension (length L × width D × height H) of about 120 × 60 × 30 mm and is provided with a main body display unit 37 composed of three LEDs for displaying detection information. ing. Similar to the detection unit display unit 36, the main body display unit 37 displays one of three signal states of no signal, control light, and communication light. The photodetector main body 32 also has a function of emitting a sound to notify the distinction between the three signal states as a detection result. Further, the photodetector main body 32 is provided with a display panel 38 made of a liquid crystal display device or the like. Usually, the converted value (dBm) of the signal light intensity transmitted through the optical transmission path is a numerical value on the display panel 38. Is displayed. This conversion value is obtained by converting the value of the light intensity measured by the light detection unit 31 using the optical coupling degree of the light detector 30 measured in advance. The degree of optical coupling also depends on the structure of the light leakage component 10, so that the measurement accuracy is inferior to that obtained when the optical transmission line is switched and the optical signal transmitted directly from the end face of the optical transmission line is measured. As such, it has sufficient accuracy. In this embodiment, the optical fiber used as the optical transmission line is selected as a type that is resistant to bending, and the coating color of the optical fiber is designated white, so that the measurement accuracy is suppressed to approximately 1 dB or less.

  Therefore, this detector has a function of converting the measured value into the intensity of the signal light propagating through the optical transmission line from the optical coupling efficiency measured in advance.

  The photodetector 30 has a function of an optical power meter. If a light receiving unit (not shown) is attached instead of the detector 31, the mode of the photodetector main body is automatically switched to the optical power meter. In this case, the display panel 38 displays the measured light intensity.

  Further, the photodetector main body 32 has a power button 39 for turning on / off the power, and a sensitivity correction for correcting the sensitivity of the detection unit 31 when there is an influence of external light to offset the influence of the external light. A button 40 is provided. When the power button 39 is operated and the power is turned on, an LED provided on the right side of the power button 39 is lit to display a power state in which the power is turned on. In addition, when the sensitivity correction button 40 is operated and there is no influence of extraneous light, the LED provided above the sensitivity correction button 40 is lit and ready to determine the light transmission state (Ready) It is informed that the condition is present, and the presence or absence of the influence of extraneous light is displayed.

  FIG. 7A is a cross-sectional view of the detection unit 31 when the upper case 35 with a lever constituting the housing of the detection unit 31 is broken in a plane parallel to the case surface, and FIG. It is a longitudinal cross-sectional view of the detection part 31 at the time of fracture | rupturing the detection part outer case 34 and the upper case 35 with a lever which comprise a housing | casing in a surface perpendicular | vertical to a case surface.

  As shown in FIG. 5A, the detection portion outer case 34 is configured to be slightly larger than the upper case 35 with a lever, and has a box shape with an open upper surface. The upper case 35 with a lever has a box shape with an open lower surface and is accommodated in the outer case 34 of the detection unit. Side plates 52 on which rails 51 projecting outward are formed on both outer sides of the upper case 35 with a lever, as shown in FIG. Rail grooves 53 are formed on both inner sides of the detection unit outer case 34, and the rail 51 of the upper case 35 with lever is fitted into the rail groove 53 of the detection unit outer case 34, so that the upper case 35 with lever is fitted. Moves along the rail groove 53 with respect to the detector outer case 34. In addition, a spring 54 is provided between the protrusion 34a formed on the bottom surface of the detection unit outer case 34 and the upper case 35 with a lever. Is being energized. When the lever 35a is operated to move downward in the figure against the urging force of the spring 54, the upper case 35 with lever moves downward in the figure along the rail groove 53 of the outer case 34 of the detection unit.

  A space for storing and holding the light leakage component 10 when determining the light transmission state is provided in the detection unit outer case 34 as the light leakage component holding unit 55. A convex portion 56 is provided on the inner side wall of the detection portion outer case 34 facing the light leakage component holding portion 55, and a pair of detection portion outer cases 34 on both sides sandwiching the convex portion 56 are provided with a pair of bottom portions. A light leakage component insertion guide 57 is erected. The light leakage component insertion guide 57 functions as a guide when the light leakage component 10 is inserted into the light leakage component holding portion 55, and is formed with its head protruding as shown in FIG. Thus, the function of holding the light leakage component 10 inserted in the light leakage component holding portion 55 is also achieved. The position of the upper case 35 with the lever when the lever 35 a is not operated is held at a position that covers the light leakage component holding portion 55 by the urging force of the spring 54.

  The upper case 35 with a lever is formed with a pair of optical fiber retainers 58 shaped to fit with the optical fiber folded portion 19 of the light leakage component 10, and leak light is detected between the optical fiber retainers 58. One light receiving element 59 is provided. The rail 51 formed in the upper case 35 with a lever, the rail groove 53 formed in the outer case 34, the lever 35a, and the spring 54 are optical fiber strands by the optical fiber holder 58 when the lever 35a is not operated. 11a is pressed against the bending portion 17 to form a bending portion on the optical fiber 11a, and an operation mechanism that does not form the bending portion of the bending portion with the optical fiber presser 58 and the bending forming portion 17 when the lever 35a is operated is configured. To do.

  The upper case 35 with a lever is attached with a control circuit board 60 on which a control circuit for controlling the light receiving element 59 is formed, and a trigger switch 61 for starting the optical measurement by the detection unit 31. The trigger switch 61 is inserted into a hole formed in the light leakage component insertion guide 57 shown on the right side of FIG. 4A, and its tip is exposed to the light leakage component holding portion 55 by the spring force of a spring (not shown). It is held in the state. When the light leakage component 10 is inserted into the light leakage component holding portion 55, the tip thereof is pushed downward in the figure against the spring force. When the trigger switch 61 detects this state change, the trigger switch 61 outputs a trigger signal to the control circuit board 60 to start measurement by the detection unit 31. The optical signal detected by this measurement is converted into an electric signal by the light receiving element 59 and sent to the photodetector main body 32 via the coaxial cable 33 by the control circuit of the light receiving element 59 formed on the control circuit board 60. . The photodetector main body 32 is provided with a control circuit for measuring the light intensity of the optical signal measured by the light receiving element 59 and discriminating the transmission state, and the optical transmission state is discriminated by this control circuit. These results are displayed on the detection unit display unit 36 of the detection unit 31 and the main unit display unit 37 of the photodetector main body 32, and are further expressed by sound emitted from the photodetector main body 32.

  Further, the intensity of the optical signal transmitted through the optical transmission path is displayed on the display panel 38 of the photodetector main body 32.

  The light detector 30 configured separately from the optical transmission path in this way includes a light receiving element 59 that measures an optical signal leaking from a curved portion formed in the optical fiber strand 11a by being bent. And a photodetector main body 32 including a control circuit that performs transmission state discrimination control of an optical signal measured by the light receiving element 59.

  The optical transmission discriminator includes a light leakage component 10 and a light detector 30, and the one light leakage component 10 has a curve forming portion having a curved shape of a curved portion formed in the optical fiber 11 a. 17, and the other optical detector 30 presses the optical fiber 11 a against the bending portion 17 to bend the optical fiber 11 a along the curved shape of the bending portion 17. Is provided.

  In the optical fiber retainer 58, a groove 62 having an effective depth of 0.25 mm and an effective width of 1.0 mm is formed in the length direction of the optical transmission line to be inserted. This groove depth is set within ± 0.1 mm of the outer diameter of the optical fiber 11a, and is equal to the outer diameter of the optical fiber 11a. The groove width was set to be equal to or larger than the outer diameter of the optical fiber 11a and equal to or smaller than the width of the light receiving surface (not shown) of the light receiving element 59. The sector radius of curvature of the optical fiber retainer 58 is the same as that of the optical fiber folded portion 19 of the light leakage component 10 and is set to about 9 mm. In addition, the side surface of the optical fiber retainer 58 close to the light receiving element 59 is coated with a metal plating that reflects the optical signal to the light receiving element 59 side including the groove.

  Next, a procedure for determining the presence or absence of an optical signal propagating through the optical cord 11 on which the light leakage component 10 is mounted and the optical transmission state for confirming the detection result of the optical signal will be described with reference to FIG. 8A is a cross-sectional view showing a state in which the light leakage component 10 is inserted into the light leakage component holding unit 55 of the detection unit 31, and FIG. 8B is a light leakage of the light leakage component 10 from that state. It is a cross-sectional view showing a state in which the optical fiber turn-back portion 19 of the component main body 14 and the optical fiber retainer 58 of the detection portion 31 are fitted and held.

  When discriminating the optical transmission state, first, the lever 35a is operated, and the upper case 35 with a lever of the detection unit 31 of the photodetector 30 is slid as shown in FIG. Expose. At this time, because the upper case 35 with the lever tries to return to the state of covering the light leakage component holding part 55 by the spring force of the spring 54 provided between the outer case 34 and the upper case 35 with the lever, A constant load is applied to the lever 35a to hold the upper case 35 with the lever slid.

  Next, the light leakage component 10 with the slide cap 12 removed is set in a predetermined direction, and the light leakage component holding portion 55 between the pair of light leakage component insertion guides 57 as shown in FIG. Insert into. At this time, the concave portion 21 of the light leaking component main body 14 and the convex portion 56 of the light leaking component holding unit 55 are fitted and matched, whereby the relative position between the light leaking component main body 14 and the detection unit 31 is determined. Is done. The height position of the light leakage component main body 14 inserted in the light leakage component holding portion 55 in the depth direction of the detection portion outer case 34 is the inner surface of the detection portion outer case 34 facing the light leakage component holding portion 55. It is decided. Further, the end tube 13 on both sides of the light leakage component main body 14 is held by a pair of light leakage component insertion guides 57 and does not move from the light leakage component holding portion 55.

  After the light leakage component 10 is inserted into the light leakage component holding portion 55, when the lever 35a that has been held in a state of being slid by applying a certain load is released, the upper case 35 with a lever leaks light by the spring force of the spring 54. Slide to the normal position covering the component holding part 55. When the upper case 35 with lever slides to the normal position, the optical fiber retainer 58 formed on the upper case 35 with lever is inserted into the optical fiber processing region 18 of the light leakage component 10, and the optical fiber is pressed by the spring force of the spring 54. The folded part 19 is fitted with a constant load. (The optical fiber retainer 58 has a shape that fits with at least a part of each optical fiber folded portion 19.) When the optical fiber retainer 58 is fitted with the optical fiber folded portion 19, FIG. As shown, the optical fiber 11a is sandwiched between the optical fiber folded portion 19 and the optical fiber retainer 58 and deformed along the curved forming portion 17, the optical fiber folded portion 19 and the flat portion 20. This state is stably held by the operation mechanism. That is, the optical detector 30 has a holding structure that is separate from the optical transmission line and holds and holds the light leakage component 10 at the time of measurement, a part of which is fitted to each other, and the fitting state is stably held. It has. When the optical fiber retainer 58 is fitted to the optical fiber turn-back portion 19, the tip of the trigger switch 61 is pushed and slid by the end tube 13 of the light leakage component 10, and the measurement start (not shown) installed on the control circuit board 60 is started. Switch is pressed, and the detector 31 starts measurement.

  If an optical signal is transmitted to the optical fiber strand 11a by the start of the measurement, the optical signal leaks only from the optical transmission line bending portion which is a curved portion of the bending portion 17 of the optical fiber strand 11a. At this time, the light receiving element 59 is double-sealed by the detection portion outer case 34 of the detection portion 31 and the light leakage component main body 14 of the light leakage component 10, so that it is affected by sunlight and other natural noises. Instead, only leakage light from the curved portion of the optical fiber 11a is detected.

  FIG. 2C is a longitudinal sectional view showing a fitting state between the optical fiber folded portion 19 of the light leakage component main body 14 and the optical fiber presser 58 of the detection portion 31. As shown in FIG. 3C, the optical fiber 11a sandwiched between the optical fiber folded portion 19 and the optical fiber retainer 58 is accommodated in the groove 62 of the optical fiber retainer 58. The curved state is maintained without being excessively stressed. At this time, the shortest distance between the surface of the optical fiber 11a and the light receiving end surface (not shown) of the light receiving element 59 in the bending portion 17 when determining the optical transmission state is set to be about 1.7 mm. That is, the shortest distance between the optical transmission line surface of the optical fiber 11a bent along the curved shape of the bending portion 17 by the optical fiber presser 58 and the light receiving surface (not shown) of the light receiving element 59 is 2 mm or less. Is set to This value indicates that the distance between the outer surface of the light receiving element 59 and a light receiving surface (not shown) inside the light receiving element 59 is about 1.5 mm, and the outer surface of the light receiving element 59 and the optical transmission line surface of the optical fiber 11a. Is set to 0.5 mm as short as possible.

  Therefore, when determining the optical transmission state using the optical transmission discriminator according to the present embodiment, the handling work of the detection unit 31 of the photodetector 30 is mainly performed, and the photodetector main body 32 of the photodetector 30 is not illustrated. Is attached to the operator's neck or a wall in the vicinity of the work place, and the determination result is confirmed by the sound emitted from the detector main body 32 and the detection unit display unit 36. Further, it is confirmed on the main body display unit 37 of the photodetector main body 32, and the workability is improved.

  Further, the display panel 38 displays the intensity of the optical signal transmitted through the optical transmission path converted from the measurement result.

  The optical transmission discriminator was evaluated using a light source having a wavelength of 1.31 μm and a wavelength of 1.55 μm. As a result, when an optical signal having a wavelength of 1.55 μm is transmitted to the optical cord 11, the insertion loss of this optical transmission discriminator is about 0.8 dB. This insertion loss is an optical transmission in a general optical transmission system. It was confirmed that the size was not an inhibitory factor. Similarly, when an optical signal having a wavelength of 1.31 μm is transmitted to the optical cord 11, the detection limit of the optical signal is about −45 dBm, which is less than the minimum signal light intensity (about −40 dBm) in a general optical transmission system. It was confirmed that. In addition, these measurements are very stable and excellent in reproducibility. In any test, the variation in insertion loss at a wavelength of 1.55 μm is ± 0.05 dB or less, and at a wavelength of 1.31 μm. The variation in the detection limit of the optical signal was ± 0.2 dB or less.

  From these results, it is determined that the present optical transmission discriminator can discriminate the transmission state of the optical signal with both wavelengths of 1.31 μm and 1.55 μm without hindering the optical transmission state. .

  A general light that does not include the light leakage component 10 by using a typical commercially available core contrast device, such as disclosed in Patent Literature 1 and Patent Literature 2, for the transmission state discrimination test. A cord (standard single mode optical fiber, outer diameter 2.0 mm, length 3 m, with SC connectors at both ends) was used. As a result, when an optical signal having a wavelength of 1.55 μm is transmitted, the insertion loss of the optical fiber contrast device is about 2.5 dB. It has been found that it may become an obstacle. Moreover, as a result of performing the same test with an optical signal having a wavelength of 1.31 μm, the detection limit of the optical signal was about −12 dBm. Also, these insertion loss and detection limit values were poorly reproducible and varied widely. Therefore, in this case, when a weak optical signal is transmitted in a general optical transmission system, it has been confirmed that there is a possibility of erroneous determination that the transmission path is inactive.

  The comparative test was performed using an optical fiber cord having an outer diameter of 2 mm. However, the basic characteristics of the present optical transmission discriminator do not depend on the outer diameter of the optical cord 11 or the like because of its characteristic structure of measuring the optical fiber strand 11a with the light leakage component 10; The characteristics of the cord contrast greatly depend on the structure of the optical fiber cord to be measured, and it is expected that the detection characteristics are greatly deteriorated in the case of an optical cord having a large outer diameter. In addition, even with an optical cord having the same outer diameter, there are various limitations on optical transmission state discrimination using a conventional cord contrast device, such as measurement being impossible when a nylon cord is used inside.

  From these results, the conventional cord contrast device is not suitable for use as a means for discriminating the live line state as an optical transmission discriminator, and the measured value during measurement is not stable due to structural problems. It seems that it is not appropriate to use it as a simple measuring device for transmission signal light intensity or as a monitor for measuring changes in signal light intensity over the medium to long term.

  Using optical fiber cords with an outer diameter of 2.0 mm using white coated optical fiber strands, ten optical cords 11 with light leakage components are prepared, and these optical cords can be simply connected without changing each of them. Was measured at a wavelength of 1.55 μm. The signal light intensity to be measured was set to about −20 dBm. The signal light was changed to a single polarization using a polarization controller, and the fluctuation of the measured value was obtained by rotating the polarization plane. At that time, a symmetrical V-groove having an effective depth of 0.25 mm and a central angle of 90 degrees is formed at the center of the curved forming portion 17 of the light leakage component 10 along the length direction of the curved surface. Applied aluminum plating.

  When 10 measurements were performed on all the samples, the PDL error of the signal light intensity measurement value was 0.2 dB or less, and the measurement error of the measurement value was ± 0.2 dB or less including reproducibility. As a result, it was confirmed that there is practicality as a power checker for optical transmission lines.

  The reproducibility error of the measured value was 0.1 dB or less and was very stable.

  When the optical transmission line discriminator according to the present invention is applied to a fan-out optical fiber cord or the like, it is necessary to cope with a plurality of coated-color optical fiber strands. Therefore, when the dependence of the light detection efficiency of the optical transmission discriminator on the optical fiber coating color was measured, it was found that there was a difference in detection efficiency of about 5 dB at the maximum.

  Therefore, in order to correct the detection efficiency, the detection efficiency of the light leakage component 10 was measured, a correction value was calculated, and recorded on the slide cap 12 as a two-digit alphanumeric identification code. In addition, the software of the detector has been improved so that the identification code is input during measurement.

  By applying this identification code, an optical fiber cord with a light leakage part using optical fiber strands of four colors (blue, white, brown, ash) was created, and a transmission light intensity measurement test was conducted at a wavelength of 1.55 μm. . As a result, as in the above example, the measurement error was ± 0.2 dB or less including reproducibility.

  Thus, it was confirmed that the dependence of the detection efficiency on the optical fiber coating color can be corrected by introducing the identification code. In principle, the detection efficiency can be corrected even when optical fiber strands other than these colors are used, and when the cutoff wavelength of the optical fiber strand is significantly different or the optical fiber strand It is possible to correct a difference in detection efficiency caused by various factors such as a difference between coating material manufacturers.

  FIG. 9 is a graph showing the results of testing the stability of the detection light required when the present optical transmission discriminator is used as an optical monitor for examining the long-term soundness of the optical transmission line. The vertical axis of the graph represents the received light intensity [dBm] of the optical signal measured by the light receiving element 59, and the horizontal axis represents the measurement time [h]. Here, the measurement wavelength was 1.55 μm. This measured value is not the converted transmission signal light intensity displayed on the display panel 38 of the photodetector main body 32 but the actual value output from the output terminal of the control circuit of the photodetector main body 32 (not shown). .

  The intensity change of the detection light was stable within 0.3 dB even after about 1500 hours. As a result, for example, fluctuations in transmitted light intensity of about 0.4 dB can be monitored for a long time. Further, the fluctuation of the measured value in FIG. 9 is caused by a long-term slight drift. This drift is considered to be the remaining component of the drift that could not be suppressed due to the effect of the initial annealing treatment of the leaking part. Regarding the influence of this drift, it is possible to improve the determination limit by correcting the change of the reference value due to the drift. When this drift correction is performed, the detection limit of the change in the transmitted light intensity of the optical transmission line is set to 0.2 dB. It will be possible to:

  In addition, ITU-T G. Ten optical cords with a light leakage part with an outer diameter of 2 mm were prepared using optical fibers compliant with the 657.B3 recommendation, and a core-wire control test was performed using them. Here, the sectoral curvature radius R of the curved forming portion 17 of the light leakage component 10 is set to 2.5 mm, and the sectoral curvature radius r of the optical fiber folded portion 19 and the length of the flat portion 20 are optimized accordingly. did.

  A 270 Hz modulated light source having a wavelength of 1.31 μm and an intensity of −10 dBm was used as a control light source, and the test was performed at a position of about 10 km from the control light source. The measurement was performed 100 times, but all detected control light normally. The insertion loss at the time of measurement was at most 0.1 dB. Further, no abnormality was observed in the appearance of the optical fiber in the vicinity of the bending portion 17 after the test, and no optical loss occurred as an optical fiber cord.

  For comparison, the conventional ITU-T B.I. 657. An optical fiber cord corresponding to an optical fiber cord using an optical fiber recommended by A1 is used. A similar test was performed on an optical fiber cord having an outer diameter of 2 mm using an optical fiber compliant with the 657.B3 recommendation, but no control light was detected. In the case of a conventional optical fiber contrast device, an ITU-T G. 657. Although it is considered that the optical fiber cord conforming to the B3 recommendation can be used for the optical fiber cord, it is considered that the optical fiber cord used in actual use is not practical.

  As described above, according to the optical transmission discriminator according to the present embodiment, the coating removal portion of the optical cord 11 in the state of the optical fiber 11a is held in the optical transmission path by the light leakage component 10. The optical fiber 11a held by the light leakage component 10 is pressed against the curve forming portion 17 by the optical fiber presser 58 when the bend forming portion 17 and the optical fiber presser 58 are fitted, so that the curve forming portion 17 is pressed. Are bent along a curved shape of the optical transmission path to form a curved portion of the optical transmission path. When determining the transmission state of an optical signal, an optical signal propagating through the optical transmission line leaks from the curved portion of the optical transmission line, and the leaked optical signal is a light receiving element provided in a photodetector 30 separate from the optical transmission line. 59.

  For this reason, the measurement of the leaked light is performed on the optical signal leaking from a part of the coating removing portion of the optical cord 11 in the state of the optical fiber 11a, and is disclosed in Patent Literature 1, Patent Literature 2, and the like. The light detection efficiency can be greatly improved and stabilized as compared with the case where the conventional optical fiber for detecting a core wire is simply used.

  In addition, the optical transmission line used for the measurement is provided with a light leakage component 10 in a part thereof. The optical leakage component 10 is stored and held separately from the optical transmission line during measurement. Since the photodetector 30 has a structure that fits partly with each other and stably holds the fitted state, it is inserted more than when a conventional optical transmission discriminator disclosed in Patent Document 5 is used. The reproducibility and stability of optical characteristics such as loss and detection value can be greatly improved.

  Further, the optical fiber 11a at the coating removal portion of the optical cord 11 is fixed freely at both ends in an open state with a predetermined length between the pair of optical fiber fixing portions 15, so that the optical fiber 11a is fitted. And in a non-fitted state, it is possible to stably ensure a state in which unnecessary extension stress, compression stress, and local bending do not occur.

  Further, in the light leakage component main body 14, since the optical fiber processing region 18 is provided between the portion corresponding to the transmission path bending portion formed by the bending forming portion 17 at the time of fitting and the optical fiber fixing portions 15 on both sides thereof, The optical fiber 11a is guided from the curved portion to the optical fiber fixing portion 15, and the bending radius of the optical fiber 11a at the time of non-fitting can be ensured to be larger than a certain value. It is possible to stably prevent an increase in optical loss depending on the optical fiber and to ensure long-term reliability of the optical fiber to be used.

  As a result, in order to apply the techniques disclosed in Patent Documents 4 to 6 to optical fiber cores, optical fiber cords, optical fiber cables, and the like, new details such as optical fiber cores, optical fiber cords, optical fiber cables, etc. A new holding structure, a new structure for generating leakage light only when fitted, and not causing an increase in light loss when not fitted, and a new structure required for the photodetector 30 in order to stabilize the detection light An optical transmission discriminator having a structure and excellent in long-term reliability will be provided.

  In the light leakage component 10 of the present invention, the prototype was made without fixing the optical fiber 11a in the same manner as the optical fiber connector at the beginning, but in this case, the pre-length changes due to repeated measurement. As a result, it has been found that this causes bending of the optical fiber 11a. Therefore, when the optical fiber strands 11a are tried to be fixed at the optical fiber fixing portions 15 on both sides inside the light leakage component 10, the occurrence of bending of the optical fiber strands 11a is fundamentally suppressed. This is one factor that led to the proposal of a new configuration of the optical transmission discriminator of the present invention.

  Further, according to the optical transmission discriminator according to the present embodiment, the optical fiber 11a held by the light leakage component 10 is fitted into the light leakage component by the optical fiber retainer 58 provided in the photodetector 30 when fitted. By being pressed down by the curve forming portion 17 provided in 10, the curve forming portion 17 is bent along the curve shape of the curve forming portion 17 to form an optical transmission line bending portion. The optical signal leaked from the curved portion of the optical transmission path is used for optical transmission discrimination.

  Thus, by providing the light leakage component 10 with the curve forming portion 17, the optical fiber 11 a as a coating removal portion of the optical cord 11 that is held freely between the optical fiber fixing portions 15 with a pre-length. Since the bending direction at the time of non-fitting is limited, it has an advantage that the optical fiber 11a can be easily guided to a predetermined position at the time of fitting.

  In addition, by forming the bending portion 17 integrally with the light leakage component main body 14, there is an effect that a slight step is generated at the time of fitting and the optical fiber 11 a is prevented from being bent.

  Further, by providing the optical fiber holder 58 in the photodetector 30, the light leakage component 10 can be reduced in size and price.

  In the optical transmission discriminator according to the present embodiment, the length of the optical fiber 11a between the pair of optical fiber fixing portions 15 is set to a length determined by the curved structure at the time of fitting. Therefore, the pre-length of the optical fiber 11a is set to an optimum value, and the optical fiber 11a is placed between the optical fiber fixing portions 15. By being appropriately held and fixed so as to be freely movable, the optical fiber 11a has a structure that does not generate a tensile stress or a compressive stress during fitting. In addition, since the necessary minimum extra length is ensured, it is possible to effectively suppress the occurrence of loss caused by bending or the like when not fitted.

  Further, in the optical transmission discriminator according to the present embodiment, since the radius of curvature of the bending portion 17 is 1.5 mm or more and 5.5 mm or less, the wavelength dependency of insertion loss caused by the bending is minimized. This makes it possible to keep the minimum signal light intensity detectable on the short wavelength side low while keeping the insertion loss on the long wavelength side low. Widely secured than ever before.

  Further, in the optical transmission discriminator according to the present embodiment, the optical fiber processing region 18 is formed continuously with the curve forming portion 17, and the covering removal portion is bent opposite to the curve direction of the curve forming portion 17 during fitting. Of the optical fiber strand 11a as a coating removal portion formed between the optical fiber return portion 19 and the optical fiber return portion 19 and held by the optical fiber fixation portion 15 when fitted. A predetermined length that holds a part of the optical fiber fixing part 15 in a straight line without being bent, and the optical fiber 11a serving as a sheath removal part forms a part of a space that forms a curved structure when not fitted. The optical fiber alignment region is provided as the flat portion 20.

  For this reason, the optical fiber 11a between the pair of optical fiber fixing portions 15 at the time of fitting is forcibly deformed into a shape along the curved shape of the curved forming portion 17 by the curved forming portion 17 and the optical fiber presser 58. In addition, each optical fiber 11a in each flat portion 20 is held in a state close to a straight line. Therefore, it becomes easy to prevent local bending and stress from occurring in the optical fiber 11a during fitting, and it is possible to effectively suppress the occurrence of unnecessary optical transmission loss.

  On the other hand, the optical fiber 11a between the pair of optical fiber fixing portions 15 at the time of non-fitting is released from those stresses and is fixed at both ends with a predetermined pre-length. Is held curved. The curvature of curvature at this time is sufficiently larger than the curvature of curvature of the curvature forming portion 17 and the optical fiber folding portion 19 due to the contribution of the optical fiber 11a in the flat portion 20. Accordingly, the flat portion 20 exhibits an effect of stably preventing the optical fiber strand 11a in the light leakage component 10 from being excessively bent and causing an optical signal insertion loss when the transmission state is not determined. .

  Further, according to the optical transmission discriminator according to the present embodiment, the optical fiber strand 11a is formed between the pair of optical fiber fixing portions 15 in the light leakage component 10 at the time of fitting, as shown in FIG. The central angle β of the arc of the curved portion formed in the center by the portion 17 becomes equal to the sum of the central angles θ of the arcs of the curved portions formed on the both sides of the curved portion by the optical fiber folded portion 19 equally. Curved.

  For this reason, in the light leakage component 10 when determining the transmission state, the optical fiber 11a in the vicinity of the optical fiber fixing portions 15 on both outer sides of the curved portions formed by the optical fiber folded portion 19 is held in a straight line. The Accordingly, since the optical cords 11 at both ends are held in a straight line, the light leakage component 10 can be reduced in size and handled easily.

  Further, according to the optical transmission discriminator according to the present embodiment, the curvature of curvature when the optical fiber 11a that forms the sheath removal portion between the optical fiber fixing 15 portions that are freely movably fixed is not covered. The optical fiber strand 11a forming the removal portion is held at a curvature defined by the long-term reliability, and the width of the flat portion 20 as the optical fiber alignment region is set by converting from the curvature. For this reason, it becomes possible to highly suppress the occurrence of insertion loss of the light leaking component 10 when not fitted, and the mechanical strength of the optical fiber 11a is guaranteed for a long period of time. The long-term reliability of the optical fiber 11a, which is the movable part, is ensured, which greatly contributes to the long-term reliability of the light leakage component 10.

  Further, in the optical transmission discriminator according to the present embodiment, the optical fiber retainer 58 is formed with an optical fiber retainer gap as a gap in the region where the bend forming portion 17 is fitted. The optical fiber retainer 58 is fitted to at least a part of each optical fiber turn-back portion 19 to be bent along the curved shape by the bending forming portion 17 to form a light transmission path bending portion. The bending portion generates an optical insertion loss according to the design and can deform the optical fiber strands 11a of the respective optical fiber folded portions 19 along these shapes. An increase in fiber transmission loss can be prevented.

  In addition, when each optical fiber retainer 58 is formed of a material that does not transmit an optical signal, the optical fiber retainer 58 has a shape that forms a predetermined gap with the bend forming portion 17, and the optical transmission path curved portion Therefore, the optical signal emitted to the outside of the optical transmission line is not blocked by the optical fiber holder 58 and is efficiently measured by the light receiving element 59 of the photodetector 30.

  Further, according to the optical transmission discriminator according to the present embodiment, the curved surface that comes into contact with the optical fiber 11a serving as the coating removal portion at the portion that fits with each optical fiber retainer 58 of each of the optical fiber folded portions 19 is provided. Since the curvature radius r is 1.3 times or more of the curvature radius R of the curved surface of the curve forming portion 17, transmission loss occurs due to the bending of the optical fiber 11a at the optical fiber folded portion 19 when determining the transmission state. Can be minimized, and the influence on the optical transmission state can be minimized. However, 1.3 times is the minimum value converted from the measured value, and in the case of the present embodiment, this is doubled to effectively suppress the occurrence of transmission loss in the optical fiber folding section 19.

  In addition, according to the optical transmission discriminator according to the present embodiment, the optical fiber turning portion 19 having a curved surface that is curved opposite to the bending direction of the curved forming portion 17 and that is continuous with the curved shape of the curved forming portion 17 is provided. 17 is formed in the optical fiber folding region on both sides of the optical fiber, and the optical fiber folding part 19 is fitted to face the optical fiber holder 58 when fitted, and one of the optical fiber strands 11a serving as a coating removing part is interposed therebetween. By stably holding the part, the position of the optical fiber 11a in the light leakage component main body 14 at the time of transmission state determination is stabilized, and the local position of the optical fiber 11a between the optical fiber fixing parts 15 is stabilized. It becomes possible to suppress the occurrence of bending.

  The optical transmission discriminator according to the present embodiment has an effective depth within the outer diameter ± 0.1 mm of the optical fiber 11a, an effective width equal to or larger than the outer diameter of the optical fiber 11a, and the light receiving element 59. A groove 62 having a width equal to or smaller than the width of the surface is formed in the length direction of the optical transmission path in at least one portion of the bending portion 17, the optical fiber retainer 58, or the optical fiber folded portion 19.

  For this reason, the optical fiber 11a between the pair of optical fiber fixing portions 15 at the time of determining the transmission state is formed by the groove 62 formed in the optical fiber retainer 58 in the length direction of the optical transmission line. The optical fibers are aligned in the length direction of the optical transmission line without applying stress from the side surface and without increasing the distance between the optical fiber and the light receiving element 59. For this reason, it becomes possible to stabilize the position of the optical fiber in the vicinity of the curved portion formed in the optical fiber strand 11a when determining the transmission state, and it is possible to prevent the light receiving efficiency from being lowered due to a positional factor. It is possible to stably improve the optical coupling degree between the curved portion of the line 11a and the light receiving element 59.

  Further, in the optical transmission discriminator according to the present embodiment, the cross-sectional shape of the groove formed in the length direction of the optical transmission path in at least one portion of the bending portion 17, the optical fiber retainer 58, or the optical fiber turn-back portion 19 is right and left. The shape is based on a symmetric V-groove, and a light reflecting surface is formed on at least a part of the inner surface of the groove.

  According to this configuration, not only the leaked light emitted from the surface of the optical fiber facing the light receiving element of the detection unit, but also the leaked light emitted from the surface of the optical fiber in a direction perpendicular to the optical fiber surface efficiently enters the light receiving element. Therefore, not only does the light detection efficiency increase significantly, but the polarization dependency of the light detection efficiency is greatly eliminated, and reproducibility is not dependent on the polarization state of the optical signal transmitted through the optical fiber. In addition, it is possible to obtain light detection characteristics with excellent stability.

  In addition, the optical transmission discriminator according to the present embodiment has the surface of the optical fiber 11a as the optical transmission line bending portion bent along the curved shape of the bending forming portion 17 at the time of fitting, and the light receiving element 59 receives light. Since the shortest distance to the surface is 2 mm or less, the distance between the curved portion of the optical fiber 11a and the light receiving element 59 when determining the transmission state is minimized, and the optical transmission of the optical fiber 11a is performed. It is possible to improve the optical coupling efficiency between the path bending portion and the light receiving element 59.

  In addition, since the optical transmission discriminator according to the present embodiment is subjected to the light reflection process for reflecting the optical signal on the side surface of the optical fiber holder 58 on the light receiving element 59 side, the optical signal coupling efficiency can be improved. It becomes possible.

  In addition, according to the optical transmission discriminator according to the present embodiment, the optical fiber holder 58 and the optical fiber presser 58 at the time of fitting are held by the operation mechanism that holds the fitting between the light leakage component 10 and the photodetector 30 when the operation lever 35a is not operated. The optical transmission line bending portion is formed in a part of the optical fiber 11a by the action on the bending forming portion 17, leakage light is generated in the optical transmission line bending portion, and leakage light is measured. For this reason, since the operation mechanism is not operated at the time of determining the transmission state performed by forming the bending portion in the optical fiber strand 11a by the optical fiber holding portion 58 and the bending forming portion 17, the optical fiber holding portion 58 is caused by the operation. The relative position with respect to the bending portion 17 does not change, the fitting state between the optical fiber retainer 58 and the bending portion 17 is stabilized, and the reproducibility of leakage light measurement is improved. Therefore, the insertion loss of the optical transmission line and the optical coupling degree between the curved portion of the optical fiber 11a and the light receiving element 59 at the time of determining the transmission state are stabilized, and the difference in the measured value of the leaked light caused by human factors is minimized. It becomes possible to limit to the limit. In addition, since the insertion loss and optical signal reception efficiency at the time of determining the transmission state are stable over the long term, an optical transmission discriminator is used as an optical monitor for measuring the medium to long-term stability of the optical signal in the optical transmission path. It becomes possible.

  Further, according to the optical transmission discriminator according to the present embodiment, the optical detector 30 is separated into the detector 31 and the optical detector main body 32, and the optical transmission line bending portion formed as a part of the optical fiber 11a. By configuring the light receiving element 59 for detecting the leaked light from the light detector main body 32 as a separate detection unit 31, the detection unit 31 can be greatly reduced in size, and the workability of the optical transmission state determination work is improved. Greatly improved. In addition, when an optical transmission discriminator is used as an optical monitor that measures the medium to long-term stability of optical signals in the optical transmission line, the volume of space occupied by the optical transmission discriminator in the vicinity of the optical transmission line is greatly increased. An optical monitor that is reduced and has excellent storage and retention is provided.

  Moreover, it becomes possible to share the photodetector main body 32 with respect to the plurality of photodetectors 31, and efficient operation becomes possible.

  In the present embodiment, the photodetector 30 has a function of converting the measured value into the signal light intensity transmitted through the optical transmission line from the optical coupling efficiency measured in advance.

  In the optical transmission discriminator according to the present invention, it is possible to specify the optical coupling characteristics within a certain range at the time of manufacture, so that the intensity of the transmission signal can be converted. In addition, the optical transmission discriminator according to the present invention is excellent in reproducibility and stability of measurement values, and thus can perform measurement with excellent reliability.

  In the conventional optical fiber contrast device, the optical transmission line to be measured cannot be specified, and the reproducibility and stability of the optical coupling degree is inferior, so that the intensity of the transmission signal cannot be converted. In this case, the measurement value is also due to human factors by the operator, and the measurement value of the detector is further inferior in reliability. Therefore, the main function is to determine only the presence or absence of control light that ensures the intensity.

  Further, in the present embodiment, the light leakage component 10 is characterized in that an identification code indicating a correction value for correcting a solid difference due to a light leakage component having a light coupling efficiency measured in advance is described.

  In the optical transmission discriminator according to the present invention, if an identification code is introduced, a difference in the coating color of the optical fiber, a difference in the cutoff wavelength of the optical fiber, a difference between manufacturers of the coating material of the optical fiber, etc. Thus, it is possible to correct individual differences in light leakage components due to various factors.

  Further, in the present embodiment, the photodetector 30 has an optical line monitoring function and is held in the middle and long term in a state where the light leakage component 10 is held.

  In the optical transmission discriminator according to the present invention, the optical transmission path discriminator can check the soundness such as the stability of the transmission characteristics of the optical transmission path. As a result, it is possible to analyze an unexpected transmission loss abnormality, instantaneous interruption, output stability of the light source in use, etc. almost simultaneously with the occurrence of these situations, and early response is possible.

  Further, in the present embodiment, the photodetector 30 has a core line contrast function, and the light leakage component 10 is applied to an optical fiber cord using an optical fiber having a minimum allowable bending radius of 5 mm or less. And

  In the optical transmission discriminator according to the present invention, the optical fiber cord is superior in light detection efficiency at each stage as compared with the conventional optical fiber contrast device. . 657. The optical fiber cord using an optical fiber that is strong in bending and has a minimum allowable bending radius of 5 mm or less, such as an optical fiber that complies with the B3 recommendation, can be reliably controlled. Furthermore, since the wavelength dependence of detection efficiency is greatly suppressed, low loss core line contrast is possible in almost the entire range of the single mode wavelength range, and at the same time, live line discrimination is also possible. It is possible to prevent accidents that accidentally disconnect the working line.

  Further, in the present embodiment, since the optical cord 11 that is an optical transmission body includes the light leakage component 10, the present optical transmission body is installed in a necessary place such as a station building or a relay station in advance. The optical transmission discrimination by the optical transmission discriminator of the form becomes possible.

  In the present embodiment, the configuration in which the light leakage component 10 is attached to the optical cord 11 has been described as an example. However, the light leakage component 10 may be attached to another optical transmission body such as an optical fiber core or an optical cable. It is not limited to the mode shown. In some cases, the light leakage component 10 may be configured in an optical fiber core state or the like instead of the optical fiber strand 11a, and the optical fiber held inside the light leakage component 10 is limited to the optical fiber strand 11a only. It is not something. Moreover, although the adhesive was used for the fixing method of the optical cord 11 in the optical fiber fixing | fixed part 15, you may fix using methods, such as caulking.

  If the optical fiber in the light leakage component 10 is an optical fiber core, the light detection efficiency is reduced, but the work of processing the optical cord and mounting the light leakage component 10 is simplified, and a tight structure has already been created. In addition, there is an advantage that application (processing) to an existing optical fiber cord becomes easy.

  Further, in this embodiment, the optical signal reflection metal plating applied to the optical fiber holder 58 may be replaced by another method such as a dielectric multilayer filter, or the optical signal reflection process may not be performed.

  Further, the surface of the curve forming portion 17 may be subjected to a signal light reflection process. In this case, the price of the light leakage component 14 increases, but the degree of optical coupling when detected by the photodetector 30 is improved by several dB.

  Further, the detection unit 31 may include the optical fiber folding unit 19. The optical fiber turn-back portion 19 may be omitted.

  In this embodiment, the case where the flat portion 20 is provided as the optical fiber alignment region has been described. However, the optical fiber alignment region does not have to be the flat portion 20. For example, an optical fiber alignment region may be provided as a space between the optical fiber folded portion 19 and the optical fiber fixing portion 15, and in this case, the effect of the optical fiber alignment region is effective.

  Further, in the present embodiment, the case where the light leakage component 10 includes the curve forming unit 17 and the detection unit 31 includes the optical fiber retainer 58 has been described. However, the present invention is not limited to this configuration. For example, the detection unit 31 may include the curve forming unit 17 and the optical fiber holder 58.

  According to this configuration, the light leakage component 10 does not include, for example, the curve forming portion 17, the optical fiber turn-back portion 19, and the flat portion 20, and between the optical fiber fixing portions 15 of the light leakage component 10 is not measured. There is no structure for holding the optical fiber 11a, including the time of measurement, and it is configured by a space corresponding to the central curve forming portion 17 and optical fiber processing regions 18 on both sides thereof. At this time, the light leakage component main body 14 of the light leakage component 10 includes both upper and lower side walls, an opening 22 and an optical fiber fixing portion sandwiching the opening 22 of the light leakage component 10 shown in FIG. It is sufficient if it is composed of 15 parts, which is one of the simplest structures.

  In this case, the optical fiber 11a held by the light leakage component 10 is the same as the optical fiber retainer 58 provided in the detection unit 31 and the detection unit 31 when the light leakage component 10 and the photodetector 30 are fitted. By being pressed against the curve forming portion 17 provided in the curve, the curve forming portion 17 is bent along the curve shape. Then, the optical signal leaked from the curved optical fiber 11a (light transmission path curved portion) is used for optical transmission discrimination.

  As described above, since both the bending portion 17 and the optical fiber retainer 58 are provided in the detection portion 31, the structure of the part for forming the bending portion in the coating removal portion of the optical cord 11 becomes simple, and precise machining accuracy is required. It will not be. For this reason, it is possible to further reduce the price while maintaining the performance of the optical transmission discriminator. Further, it is possible to improve the conversion accuracy when the measured value is converted into the signal light intensity transmitted through the optical transmission line from the optical coupling efficiency measured in advance. Further, by providing in advance in the optical transmission line of the optical transmission system, the light leakage component 10 having only the structure for holding and fixing the coating removal portion of the optical transmission line and the structure for fitting to the detection unit 31, By replacing the bending portion 17 provided in the detection unit 31 without replacing the light leakage component 10 already installed in the optical transmission system, the bending shape of the bending portion 17 is changed, and the optical transmission is performed. It becomes possible to appropriately change the insertion loss of the discriminator, the optical signal reception efficiency, and the like. In addition, when the optical transmission discriminator is applied to an optical monitor that monitors the medium to long-term stability of the optical transmission path, it is possible to flexibly cope with different required specifications.

  In the optical transmission discriminator according to the present embodiment, the optical fiber retainer 58 forms an optical fiber retainer gap as a gap in the region of the curve forming portion 17, but an optical signal passes through the region of the curve forming portion 17. It is good also as a structure which integrated the transparent member part as a predetermined | prescribed light passage member part and the part fitted to a part of optical fiber folding | turning area | region at the time of a fitting. In this case, by using a material that does not allow the optical signal to pass through the part that fits with a part of the optical fiber folded region during fitting, a part of the optical signal leaking from the curved portion of the optical transmission path is received by the light receiving element 59. Efficiency can be improved. However, this is not the case when the optical signal reflection process is applied to the boundary between the light passing member through which the optical signal passes and the member in the optical fiber folding region.

  Further, the slide cap 12 is not necessarily integrated, and may not be structured to be removed from the light leakage component main body 14 at the time of measurement. For example, at the time of measurement, it is separated into two from the center, and the side of the light leakage component main body 14 is slid as a rail, and the two separated slide caps 12 stay on the optical fiber fixing portion 15, and either one of the two A procedure for inserting the light leakage component 10 into the outer case 34 of the detection unit 31 by holding the slide cap 12 may be adopted. Further, the slide cap 12 remains integrated with the optical fiber fixing portion 15 when it is slid, and the slide cap 12 is held to insert the light leakage component 10 into the detection portion outer case 34 of the detection portion 31. It may be adopted.

  Moreover, although the identification code is two alphanumeric characters, the identification code is not limited to this. Bar code, two-dimensional code, IC tag (RFID), etc. may be used to support automatic reading. In this case, the identification code may be attached to the light leakage component main body. In some cases, the core management data is written in the identification code and applied to the core management system as a management tag.

  The optical transmission discriminator according to the present embodiment has an effective depth within the outer diameter ± 0.1 mm of the optical fiber 11a, an effective width equal to or larger than the outer diameter of the optical fiber 11a, and the light receiving element 59. Although the case where the groove 62 having a width equal to or smaller than the width of the surface is formed in the optical fiber retainer 58 has been described, the groove 62 does not transmit light to at least one portion of the curve forming portion 17 or the optical fiber retainer 58 or the optical fiber folded portion 19. What is necessary is just to be formed in the length direction of the transmission line.

  Further, the material of the light leakage component main body 14 is not limited to ABS resin, and may be an inorganic material, metal, rubber, or other plastic. Further, the number of the light receiving elements 59 in the detection unit 31 is not limited to one and may be two or more. Further, the detection unit display unit 36 of the detection unit 31 and the display panel 38 of the photodetector main body 32 are not necessarily required, and may be omitted depending on circumstances.

  Further, in the present embodiment, the position of the upper case 35 with the lever when the lever 35 a of the detection unit 31 of the photodetector 30 is not operated is held at a position that covers the light leakage component holding unit 55 by the biasing force of the spring 54. However, only when the lever 35a is operated to move downward in the figure against the urging force of the spring 54, it moves downward in the figure along the rail groove 53 of the detection unit outer case 34. For example, when the lever 35 is moved to the lowermost position, the upper case 35 with the lever is held at that position, and when the lever 35 is moved again to the lowermost position, the upper case with the lever is held at a position that covers the light leakage component holding portion 55. It is good also as a structure with two stable positions at the time of non-operation.

  The optical transmission discriminator according to the present embodiment is applied to an optical fiber core wire, an optical fiber cord, an optical fiber cable, and the like, so that a connection state of an optical transmission path used in an optical communication system, an optical wiring, an optical sensor system, etc. It can be used to determine the transmission state such as a live line state. Further, it can be used as a photodetector of a cord contrast device (ID tester) with improved minimum detectable signal light intensity.

  Furthermore, it is possible to apply as a transmission light intensity measuring device that simply measures the signal light intensity during transmission while maintaining the transmission state, and an optical monitor that monitors medium- to long-term changes in the optical transmission path. .

DESCRIPTION OF SYMBOLS 10 ... Light leaking part 11 ... Optical cord 11a ... Optical fiber strand 11b ... Cord jacket 11c ... Secondary coating | coated material 11d ... Strength body 12 ... Slide cap
DESCRIPTION OF SYMBOLS 13 ... End tube 14 ... Light leak component main body 15 ... Optical fiber fixing | fixed part 17 ... Curve formation part
DESCRIPTION OF SYMBOLS 18 ... Optical fiber process area | region 19 ... Optical fiber return part 20 ... Flat part 21 ... Concave part 22 ... Opening part
DESCRIPTION OF SYMBOLS 23 ... Slope 24 ... Insertion groove 30 ... Photodetector 31 ... Detection part 32 ... Photodetector main body 33 ... Coaxial cable 34 ... Detection part outer case 34a ... Protrusion 35 ... Upper case with lever 35a ... Lever 36 ... Detection part display part 37 ... Main body display unit 38 ... Display panel 39 ... Power button 40 ... Sensitivity correction button 51 ... Rail 52 ... Side plate 53 ... Rail groove 54 ... Spring 55 ... Light leakage component holding portion 56 ... Convex portion 57 ... For light leakage component insertion Guide 58 ... Optical fiber holder 59 ... Light receiving element 60 ... Control circuit board 61 ... Trigger switch 62 ... Groove

Claims (22)

A light leakage component that is installed in the optical transmission line and holds the coating removal portion of the optical transmission line that is in either the optical fiber strand or the optical fiber core, and the optical transmission line is separate A light detector having a holding structure for storing and holding the light leakage component at the time of measurement, further fitting with a part thereof, and stably holding the fitted state;
The photodetector has a light receiving element that measures a transmission optical signal leaking from an optical transmission path bending portion formed by bending a part of the coating removal portion in the light leakage component only at the time of fitting. And
A curve forming portion that is provided on any one of the light leakage component and the light detector and forms a curve shape of the light transmission path bending portion at the time of fitting;
Light that is provided on one of the light leakage component and the light detector, presses a part of the coating removal portion against the curve forming portion when fitted, and curves along the curve shape of the curve forming portion. With a fiber retainer,
The covering removal portion is fixed to a pair of optical fiber fixing portions whose both ends are configured on both sides in the length direction of the light leakage component, and has a predetermined extra length between the pair of optical fiber fixing portions. It is held freely for a predetermined length,
The light leakage component is configured such that the coating removal portion is fixed from the light transmission path curved portion to the optical fiber between a portion corresponding to the light transmission path curved portion at the time of fitting and the optical fiber fixing portions on both sides thereof. An optical transmission discriminator for discriminating a transmission state of an optical signal propagating in the optical transmission path, comprising an optical fiber processing region leading to a part. The light leakage component includes the curve forming portion;
The optical transmission discriminator according to claim 1, wherein the optical detector includes the optical fiber retainer.   The optical transmission discriminator according to claim 1, wherein the optical detector includes the bending portion and the optical fiber retainer.   The length of the sheath removing unit is set to a length determined by a curved shape when the light leakage component and the photodetector are fitted, and the optical fiber fixing unit has a surplus length determined by the length. The optical transmission discriminator according to any one of claims 1 to 3, wherein the optical transmission discriminator is held freely between the sections.   The optical transmission discriminator according to any one of claims 1 to 4, wherein a curvature radius of the curved forming portion is 1.5 mm or more and 5.5 mm or less.   The optical fiber processing region is formed continuously with the curve forming portion, and the sheath removing portion is bent opposite to the bending direction of the curve forming portion when fitted, and the optical fiber folded region. A portion of the coating removal portion formed between the optical fiber fixing portion and the optical fiber fixing portion is held in a straight line without being bent from the optical fiber fixing portion. 6. The optical fiber alignment region according to claim 1, further comprising an optical fiber alignment region having a predetermined length that becomes a part of a space forming the curved structure when the cover is removed. The optical transmission discriminator described.   The center angle of the arc formed by the optical transmission line bending portion at the time of fitting is equal to the sum of the center angles of the arcs formed by the coating removal portions of the optical fiber folded region on both sides thereof at the time of fitting. The optical transmission discriminator according to claim 6.   The curvature of curvature when the sheath removal portion is not fitted between the optical fiber fixing portions fixed in a freely movable manner contributes to the long-term reliability of the optical fiber strand or the optical fiber core wire forming the sheath removal portion. 8. The optical transmission discriminator according to claim 6, wherein the optical transmission discriminator is held at a prescribed curvature, and the width of the optical fiber alignment region is set by converting from the curvature.   The optical fiber retainer has an optical fiber holding gap portion formed as a predetermined light passing member portion or a gap through which an optical signal passes in a region fitted with the curve forming portion, and each optical fiber folded region at the time of fitting. 9. The optical transmission discriminator according to claim 6, wherein the optical transmission discriminator has a structure that fits at least a part of the optical transmission discriminator.   The curvature radius of the curved surface that contacts the coating removal portion at a portion that fits with the optical fiber retainer in each of the optical fiber folding regions is 1.3 times or more of the curvature radius of the curve forming portion. The optical transmission discriminator according to claim 9.   An optical fiber folded portion having a curved surface that is curved opposite to the bending direction of the curved forming portion and is continuous with the curved shape of the curved forming portion is formed in the optical fiber folded region on both sides of the curved forming portion, and the light 11. The fiber turn-back portion is fitted to face the optical fiber retainer when fitted, and a part of the coating removal portion is stably held between them. Optical transmission discriminator.   A groove having an effective depth within an outer diameter of ± 0.1 mm of the coating removal portion and an effective width equal to or larger than the outer diameter of the coating removal portion and the width of the light receiving surface of the light receiving element is the curve forming portion or the The optical transmission discrimination according to any one of claims 1 to 11, wherein the optical transmission discriminator is formed in at least one place of an optical fiber presser or the optical fiber folded portion in the length direction of the optical transmission path. vessel.   13. The optical transmission discrimination according to claim 12, wherein the cross-sectional shape of the groove is a shape based on a symmetrical V-groove, and a light reflecting surface is formed on at least a part of the inner surface of the groove. vessel.   The shortest distance between the surface of the light transmission path curved portion bent along the curved shape of the curve forming portion and the light receiving surface of the light receiving element when the light leakage component and the photodetector are fitted is 2 mm. The optical transmission discriminator according to any one of claims 1 to 13, wherein:   The optical fiber retainer is formed with a light reflecting surface that reflects an optical signal toward the light receiving element on at least a part of a side surface of the light passage member portion or the optical fiber retainer gap portion on the optical fiber return region side. 12. The optical transmission discriminator according to claim 9, wherein the optical transmission discriminator is any one of claims 9 to 11.   The optical transmission discriminator according to any one of claims 1 to 15, further comprising an operation mechanism that holds a fitting between the light leakage component and the photodetector when not operated.   The photodetector is separated into a detection unit including the light receiving element and a photodetector main body including a control circuit for controlling measurement of transmission state determination of an optical signal measured by the light receiving element. The optical transmission discriminator according to any one of claims 1 to 16, characterized in that:   The said photodetector has a function which converts a measured value into the signal light intensity which transmits an optical transmission line from the optical coupling efficiency measured previously, The any one of Claims 1-17 characterized by the above-mentioned. The optical transmission discriminator described.   19. The optical transmission discriminator according to claim 18, wherein the light leakage component is labeled with an identification code indicating a correction value for correcting a solid difference due to the light leakage component having a light coupling efficiency measured in advance.   The light according to any one of claims 1 to 19, wherein the photodetector has an optical line monitoring function and is held for a long period in a state where a light leakage component is held. Transmission discriminator.   2. The optical detector according to claim 1, wherein the photodetector has a core contrast function, and the light leakage component is applied to an optical fiber cord using an optical fiber having a minimum allowable bending radius of 5 mm or less. The optical transmission discriminator according to claim 20.   An optical transmission body forming the optical transmission path, wherein at least a part of the optical transmission body is defined in any one of claims 1 to 8, or 10 to 13, or 19 to 21. An optical transmission body comprising the light leakage component described above.

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