JP2013113871A - Communication light detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication light detector capable of extracting a communication light of a desired wave length from the inside of a communication light transmission line and detecting the communication light even when multiple communication lights having different wave lengths are propagating in the communication light transmission line.SOLUTION: The communication light detector comprises: a communication light transmission line where multiple pieces of communication light having different wave lengths propagate; filtering means for transmitting leakage light of a communication light having a desired wave length among pieces of leakage light of the multiple pieces of communication light having different wave lengths leaked from a light leakage part provided on the communication light transmission line while absorbing or reflecting the other pieces of leakage light of the communication lights having wave lengths not desired; and a light detection part for detecting the communication light having the desired wave length from the leakage light transmitted by the filtering means.

Description

  The present invention relates to a communication light detector for detecting communication light propagating in an optical transmission line.

  An optical communication system 100 in which a communication light detector is used is shown in FIG.

  In the equipment center 14 of the optical communication company, a communication light transmission / reception device 11 is provided, and the communication light transmission / reception device 11 is provided with an optical branching / merging device 15 connected thereto. The optical branching / merging unit 15 branches the communication light (optical signal) transmitted from the communication light transmission / reception device 11 and combines or transmits the communication light (optical signal) transmitted from a plurality of user homes 10. This is for receiving by the communication light transmission / reception device 11.

  A communication light receiving / transmitting device 12, which is an optical terminal device, is provided in a user home 10 such as each home or office. A closure 16 is attached in the vicinity of the utility pole 18, and in this closure 16, an optical branching / merging device 17 for branching the communication light from the facility center 14 and for joining the communication light from each user home 10 is provided. Is provided. Further, the communication light transmission / reception device 11 and the optical branching / merging device 17 and the optical branching / merging device 17 and the communication light reception / transmission device 12 are connected by optical fibers 13A and 13B, respectively. A communication light transmission path (optical fiber 13) that connects the receiving device 11 and the communication light receiving / transmitting device 12 is formed. Thereby, optical communication is performed between the communication light transmission / reception device 11 and the communication light reception / transmission device 12. Then, a light leakage part for leaking an optical signal propagating in the communication light transmission path is formed in the optical fiber 13B, light leaked from the light leakage part is detected, and communication light transmission of the communication light transmission line is performed. A communication light detector (not shown) provided with a light detector for monitoring the state is provided.

  As this communication light detector, Patent Document 1 discloses a light detection groove provided at a connection portion in a sleeve, joined to ends of the light transmission path, and penetrating through the core of the light transmission path, and its light detection. A light detection joined body having a refractive index matching agent filled in the groove, and a light detection unit that is provided above the light detection joined body and detects leakage light of communication light leaking through the light detection groove, A communication light detector is described in which the groove for light detection has a groove width of 50 to 150 μm along the longitudinal direction of the light detection bonded body.

  In Patent Document 2, test light having a wavelength longer than that of the working light is incident on the optical fiber to be contrasted with the optical fiber so that the wavelengths of the working light and the testing light are different from each other, and light is transmitted in the transmission state of the test light. A method for contrasting optical fibers is described in which a path is bent and a leakage test light from the bent portion is detected to compare optical fibers.

JP 2009-276627 A Japanese Patent No. 2803726

  However, in the communication light detector described in Patent Document 1, communication light transmitted from the equipment center 14 to the user home 10 (usually, a 1.5 μm wavelength band is used) and transmitted from the user home 10 to the equipment center 14. Both communication lights of the communication light to be transmitted (usually the 1.3 μm wavelength band is used) are detected, and only the communication light having one of the wavelengths cannot be detected. Therefore, even if one end of the optical fiber 13 is not connected to the user's home 10 (even if it is an unused line like the optical fiber 13C), the communication light is always transmitted from the equipment center 14, The communication light detector described in Patent Literature 1 always detects leaked light. Therefore, in the communication light detector described in Patent Document 1, it is not possible to detect only communication light from the user home 10 indicating that one end of the optical fiber 13 is connected to the user home 10, and there are many It is difficult to find an unused line (optical fiber 13 </ b> C) from the optical fiber 13.

Moreover, in the method of generating leakage light by bending an optical fiber as described in Patent Document 2, in the case of 1.5 μm wavelength band communication light, it is possible to leak relatively easily, but the 1.3 μm wavelength band. In the case of this communication light, since the optical confinement effect in the optical fiber works strongly, it is difficult to leak communication light in the 1.3 μm wavelength band. Accordingly, even in the method of contrasting the cores described in Patent Document 2, depending on the wavelength of communication light to be leaked, as in Patent Document 1, an unused line (optical fiber 13C) is selected from a large number of optical fibers 13. It is difficult to find out.
Accordingly, the present invention solves the above-described problem, and even when communication light having a plurality of wavelengths propagates in the communication optical transmission line, leakage of the communication light having a desired wavelength from the communication optical transmission line. An object of the present invention is to provide a communication light detector that can extract light and detect leakage light of the communication light.

  The present invention, which was created to achieve the above object, leaks from a communication light transmission path through which a plurality of communication lights having different wavelengths are propagated, a light leakage section provided in the communication light transmission path, and the light leakage section. Filter means for transmitting communication light having a desired wavelength and absorbing or reflecting communication light having an undesired wavelength among the plurality of communication lights having different wavelengths, and the desired wavelength transmitted by the filter means And a light detector that detects communication light having a communication light detector.

  The light leakage portion is provided in the middle of the communication optical fiber, or a light detection joined body having a light detection groove penetrating the core of the communication optical fiber and a refractive index matching agent filled in the light detection groove. Between optical connectors or optical connectors provided in the middle of a communication optical fiber, or optical connectors provided in the middle of a communication optical fiber. It may be a joint portion formed by inserting an optical fiber having a different structure / component between the communication optical fiber and the core between the joint portions.

  The filter means includes a flat plate with a hole and a wavelength selection filter, and a plurality of communication lights having different wavelengths leaking from the light leakage light portion pass through the hole of the flat plate with a hole to the wavelength selection filter. The flat plate with a hole transmits incident light that is incident perpendicularly or substantially perpendicularly to the wavelength selection filter among the plurality of communication lights having different wavelengths leaking from the light leakage portion, and the wavelength selection filter May transmit communication light having a desired wavelength among the normal incident light and reflect communication light having an undesired wavelength.

  The flat plate with holes may be coated with black paint on the bottom surface and the inner wall surface, or may be formed of a black resin.

  The communication light propagating in the communication optical transmission line is communication light having a 1.3 μm wavelength band and a 1.5 μm wavelength band, and the wavelength filter transmits the 1.3 μm wavelength band, and the 1.5 μm wavelength band. It may have a characteristic of reflecting the light.

  According to the present invention, even when communication light having a plurality of wavelengths propagates in the communication optical transmission line, the communication light having a desired wavelength is extracted from the communication optical transmission line and the communication light is extracted. It can be detected.

It is a longitudinal cross-sectional view which shows the use condition of the communication light detector which concerns on a suitable 1st Example of this invention. It is a figure which shows the relationship between the cross-sectional shape of the hole of a flat plate with a hole, and leakage light. It is a wavelength characteristic view of a 1.3 μm wavelength band transmission / 1.5 μm wavelength band cutoff filter. It is a longitudinal cross-sectional view which shows the use condition of the communication light detector which concerns on the 2nd Example of this invention. It is explanatory drawing about the optical communication system in which a communication light detector is used.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a main part of a communication light detector showing a preferred first embodiment of the present invention.

  As shown in FIG. 1, the communication light detector 1 according to the first embodiment uses, for example, an optical transmission line at an optical fiber connection part in which end parts of optical fibers as an optical transmission line are connected to each other. The state is monitored to detect the presence or absence of communication light (whether optical communication is being performed).

  The communication light detector 1 includes a light detection joined body 2 and sleeves 3a and 3b into which both end portions of the light detection joined body 2 are respectively inserted. The ferrule 104c provided in the optical connector on the facility center 14 side and the ferrule 104y provided on the optical connector on the user house 10 side are inserted into the both end faces of the optical detection joined body 2 when the communication light detector 1 is used. Is done. The ferrule 104c incorporates an optical fiber 106c on the facility center 14 side, and the ferrule 104y incorporates an optical fiber 106y on the user home 10 side.

  The optical detection joined body 2 is an optical fiber composed of a core portion that is abutted and connected to end portions (end portions on the optical fiber connection portion side) of the optical fibers 106c and 106y, and a clad portion that surrounds the core portion. 4, a ferrule part 5 provided around the optical fiber 4, a part of the ferrule part 5 is removed to form a rectangular cross section, and a storage groove 6 in which a light detection part 9 described later is stored, It comprises a light detection groove 7 having a rectangular cross section formed so as to cut the optical fiber 4 at the bottom surface of the storage groove 6 and a refractive index matching agent r filled in the light detection groove 7. The light leaking portion 16 is formed above the light detecting groove 7 and the light detecting portion 9 is formed in the opening. The light detection groove 7 may be formed so as to penetrate at least the core portion of the optical fiber 4.

  The light detection joined body 2 has both end faces in the longitudinal direction joined to the end faces of the ferrules 104c and 104y, respectively. In this optical detection joined body 2, a portion including the optical fiber 4 and the optical detection groove 7 filled with the refractive index matching agent r facing the optical fiber 4 becomes the optical transmission line 8 on the detection side.

  In the optical detection joined body 2, the core portion of the optical fiber 4 is made of the same material as the core of each of the optical fibers 106c and 106y, and the clad portion is made of the same material as the cladding of each of the optical fibers 106c and 106y. The ferrule part 5 of the light detection joined body 2 is made of the same material as the ferrules 104c and 104y and the sleeves 3a and 3b. The optical fiber 4 may be an optical fiber similar to the optical fibers 106c and 106y, or an optical waveguide.

  Since both end surfaces in the longitudinal direction of the optical detection joined body 2 are connected to the end surfaces (end surfaces on the optical fiber connecting portion side) of the ferrules 104c and 104y inserted into the communication optical detector 1 by PC (physical contact). And polished so as to be the end face of the PC. The outer diameter of the optical detection joined body 2 is the same as the outer diameter of each ferrule 104c, 104y.

  The groove 7 for light detection has a groove width of 50 to 150 μm along the longitudinal direction of the light detection bonded body 2. If the groove width is less than 50 μm, the leak light generation rate is too small to make it difficult to detect leak light, or after converting the received leak light into an electrical signal, an additional amplifier is required and the number of parts increases. On the other hand, if the groove width exceeds 150 μm, the leakage light generation rate is too large, and communication is hindered.

  For each optical fiber 106c, 106y as an optical transmission line inserted into the communication light detector 1, a single mode optical fiber made of quartz glass or a GI (graded index) type multimode optical fiber is used. When a single mode optical fiber is used as each of the optical fibers 106c and 106y, communication light in the 1.3 μm wavelength band or 1.5 μm wavelength band is used. When a multimode optical fiber is used as each optical fiber, communication light having a wavelength of 850 nm band or 1310 nm band is used.

  Returning to FIG. 1, the refractive index matching agent r filled in the light detection groove 7 has a refractive index substantially the same as that of the cores of the optical fibers 106 c and 106 y. As the refractive index matching agent r, a liquid material may be used, or a thermosetting or ultraviolet (UV) curable resin or an adhesive having a refractive index after curing of each of the optical fibers 106c and 106y. Almost the same as the core may be used.

  The sleeve 3a is for aligning the optical axis between the ferrule 104c and the light detection assembly 2, and the sleeve 3b is for aligning the optical axis between the ferrule 104y and the light detection assembly 2.

  The ferrule 104c is built in an optical connector plug (not shown) on the equipment center 14 side, and the ferrule 104y is built in an optical connector plug (not shown) on the user house 10 side. These ferrules 104c and 104y are made of ceramics or metal, and are polished so that their end faces (end faces on the optical fiber connecting portion side) become PC (physical contact) end faces.

  The sleeves 3a and 3b are made of ceramic or glass that transmits at least part of communication light (or scatters when communication light is received), or made of ceramic having a slit extending in the longitudinal direction (axial direction) of the sleeve. Glass, metal split sleeves are used. Examples of the ceramic that transmits at least a part of the communication light include zirconia ceramics.

  The communication light detector 1 further includes a light detection unit 9 that is provided above the light detection bonded body 2 and detects leakage light that leaks through the light detection groove 7. In the light detection unit 9, a PD 90 having a PD element 91 for receiving leaked light is opposed to the upper side of the light detection groove 7 together with a filter means 300 (a plate 92 with a hole and a wavelength selection filter 93 described later). And it is accommodated in the accommodation groove | channel 6 so that it may arrange | position between sleeves 3a and 3b. Then, between the PD element 91 and the light detection groove 7, a donut plate-shaped flat plate 92 with a hole and a dielectric multilayer film are used to transmit a desired wavelength and reflect (block) other wavelengths. The wavelength selection filter 93 is attached to the distal end portion of the PD 90 so that they are positioned from the light detection groove 7 side in order. In addition, the flat plate 92 with a hole may be incorporated in the storage groove 6 of the light detector, and the light detection unit 4 includes a light output member (not shown) that outputs leaked light received by the PD element 91 by visible light, A circuit board 94 on which a PD 90 is mounted and which constitutes a light detection circuit is provided. That is, the light detection unit 9 includes a PD 90 including a PD element 91, a filter unit 300 (a flat plate 92 with a hole and a wavelength selection filter 93), and a circuit board 94. In this embodiment, an inexpensive can package type PD90 is used.

  Here, the role of the filter means 300 will be described.

  A part of the communication light incident in the light detection groove 7 of the light detection joined body 2 leaks as leak light, and the leak light spreads (scatters) from the end face of the core portion of the optical fiber 4. The flat plate 92 with a hole blocks the leakage light that does not enter the wavelength selection filter 93 out of the leakage light that spreads in various directions, and the leakage light that enters the wavelength selection filter 93 perpendicularly. It is for squeezing and transmitting to the 93 side. Then, the wavelength selection filter 93 transmits an optical signal having a desired wavelength among the vertically incident leakage light to the PD element 91 side, and the PD element 91 detects the optical signal.

  As described above, the reason why the leakage light is incident on the wavelength selection filter 93 through the flat plate 92 with the hole is that the wavelength selection filter 93 is formed of the dielectric multilayer film, but the dielectric multilayer film is The wavelength selection performance is maximized when light is incident vertically, and sufficient wavelength selection performance cannot be exhibited for obliquely incident light. Therefore, the communication light detector 1 is desired. This is because it is impossible to efficiently detect an optical signal having a wavelength of (that is, an optical signal having an undesired wavelength is also detected and the signal-to-noise ratio (S / N) deteriorates).

  As a result, out of the leaked light generated in the light detection groove 7, the leaked light having a component in the vertical direction is made incident on the PD element 91, and the optical signal having a desired wavelength is input by the wavelength selective filter 93. Can be efficiently transmitted to the PD element 91 side (an optical signal having an undesired wavelength can be significantly reduced from reaching the PD element 91), so that the signal-to-noise ratio (S / N ) Can be greatly improved, and the detection performance can be improved.

  Moreover, in order to acquire the above-mentioned effect, the flat plate 92 with a hole part is 1-3 mm in thickness, the outer diameter is 5 mm, for example, and the internal diameter (hole diameter) of the hole part which is a through-hole is 0.5-. 2 mm is preferable. Further, by applying a black paint to the bottom surface of the flat plate 92 with holes and the wall surface of the hole, or manufacturing the flat plate 92 with holes with a black resin, it is possible to enhance the throttling effect of leaking light.

  Further, as the cross-sectional shape of the flat plate 92 with holes, various shapes can be adopted as shown in FIG. The flat plate 92 with a hole shields (absorbs or reflects) leaked light having a large incident angle indicated by a dotted line among the leaked light incident as indicated by arrows. 2 (a) is a flat plate 92 with a hole whose inner wall 92a has a vertical cross section over the entire region from the start to the end. FIG. 2 (b) is the same as FIG. 2 (a). Similar to the structure, the shape of the inner wall 92a is a flat plate 92 with a hole having a shape in which the start and end shapes are notched (by chamfering the hole) to facilitate manufacture, and FIG. In FIG. 2 (d), the shape of the inner wall 92a is a narrow plate 92 with a hole on the end side, and in FIG. 2 (d), the shape of the inner wall 92a is a flat plate 92 with a hole having a terminal end spread type. . In any of the flat plates 92 with holes, the hole diameter and the inclination angle can be selected as appropriate, and can be set so as to block the leaking light incident obliquely and allow the vertical blocking light to pass through. In order to facilitate detection, the one shown in FIG. 2A or 2B is desirable.

  In addition, when communication light of 1.3 μm wavelength band and 1.5 μm wavelength band propagates in the communication light transmission path, and only this 1.3 μm wavelength band is to be detected and detected, the wavelength selection filter 93 is It is desirable to have the characteristics of 1.3 μm wavelength band transmission / 1.5 μm wavelength band cutoff as shown in FIG. This characteristic is obtained when light is incident at a right angle on itself (filter surface).

  As shown in FIG. 3, the wavelength selection filter 93 allows almost 100% of the leaked light in the 1.3 μm wavelength band to pass through and blocks the leaked light in the 1.5 μm wavelength band to almost 0%.

  The operation of the first embodiment will be described.

  The photodetector 1 is attached to the communication optical transmission line (optical fiber 13) to be used. Specifically, the optical connector plug on the user house 10 side is inserted and fixed to the optical connector adapter on one end side of the optical detector 1, and the optical connector plug on the equipment center 14 side is connected to the optical connector adapter on the other end side. Is inserted and fixed, communicates in the 1.5 μm wavelength band from the equipment center 14 side toward the user home 10 side, and communicates in the 1.3 μm wavelength band from the user home 10 side toward the equipment center 14 side, Assume two-way communication.

  In this case, as shown in FIG. 1, the communication light from the equipment center 14 side passes through the optical fiber 106c in the ferrule 104c built in the optical connector plug on the equipment center 14 side, and the communication light from the user home 10 side. Passes through the optical fiber 106y in the ferrule 104y built in the optical connector plug on the user's home 10 side, and both communication lights reach the light detection groove 7 of the light detection joined body 2. When both communication lights enter the refractive index matching agent r in the light detection groove 7, a part of both communication lights leak as leaked light, and the leaked light spreads from the end face of the core portion of the optical fiber 4. The wavelength of the communication light from the equipment center 14 side and the wavelength of the communication light from the user home 10 side are different. In this embodiment, the communication light from the equipment center 14 side is in the 1.5 μm wavelength band, and the user Since the communication light from the home 10 side is in the 1.3 μm wavelength band, the leakage light includes both communication light in the 1.5 μm wavelength band and the 1.3 μm wavelength band.

  The spread leaked light reaches the flat plate 92 with holes. This leaked light is narrowed down by being absorbed or reflected by the bottom surface of the flat plate 92 with holes on the side of the light detection groove 7 and the wall surface of the holes, so that a part of the leaked light enters the wavelength selection filter 93. Not reach. Other leakage light (leakage light incident on the wavelength selection filter 93 perpendicularly or substantially perpendicularly) reaches the wavelength selection filter 93 through the hole of the flat plate 92 with a hole.

  In the present embodiment, the black paint is applied to the bottom surface of the flat plate 92 with holes and the wall surfaces of the holes.

  The wavelength selection filter 93 is made of a dielectric multilayer film, and is designed to block an optical signal in the 1.5 μm wavelength band and transmit an optical signal in the 1.3 μm wavelength band.

  The leakage light (vertical incident light) that has reached the wavelength selection filter 93 is incident on the wavelength selection filter 93 vertically or substantially perpendicularly, so that the wavelength selection function of the wavelength selection filter 93 acts effectively. Therefore, the leaked light that reaches the wavelength selection filter 93 is reflected (blocked) by the optical signal in the 1.5 μm wavelength band, the transmitted optical signal in the 1.3 μm wavelength band, and the transmitted light in the 1.3 μm wavelength band. The signal is detected by the PD element 91. The PD element 91 converts the detected (received) optical signal into an electrical signal, which is transmitted through the circuit board 94 and is visible by a light output member (for example, using a light emitting diode) of the light detection unit 9. It is converted into light and output.

  In other words, even if there are a plurality of wavelengths of communication light (optical signal) propagating in the transmission path, it is possible to extract only an optical signal having a desired wavelength, and this optical signal is converted and output. The operator can easily confirm whether or not the communication optical transmission line is used by visually checking the presence or absence of light.

  Therefore, according to the communication light detector 1, by using the filter means 300, even if communication light having a plurality of wavelengths propagates in the communication light transmission line, the communication light detector 1 can receive the desired light from the communication light transmission line. It is possible to take out communication light of a wavelength of and detect the communication light. Therefore, it is possible to easily determine whether the communication light transmission path to which the communication light detector 1 is attached is a used line (detecting communication light) or an unused line (not detecting communication light).

  In the communication light detector 1 according to the second embodiment shown in FIG. 4, the PD element 91 is located on the ferrule 104 c side (downstream side of 1.3 μm wavelength band communication light) from the portion directly above the light detection groove 7. The place is shifted.

  In general, it is known that the position at which the intensity of leaked light reaches the maximum value is slightly shifted from the light detection groove 7 to the communication light receiving side as viewed from the communication light transmitting side. Accordingly, when communication light of 1.3 μm wavelength band transmitted from the communication light receiving / transmitting apparatus 12 is mixed with communication light of 1.5 μm wavelength band transmitted from the communication light transmitting / receiving apparatus 11, The leakage light of the communication light in the 1.5 μm wavelength band can be output with the maximum intensity at the position slightly shifted from the light detection groove to the communication light receiving / transmitting device 12 side, and conversely, the communication light receiving / transmitting device 12. The leakage light of the communication light in the 1.3 μm wavelength band from is obtained at the maximum intensity output at a position slightly shifted from the light detection groove 7 toward the communication light transmitting / receiving device 11 side.

  For this reason, in order to detect the communication light of the 1.3 μm wavelength band transmitted from the user's home 10, the position where the leakage light intensity is maximum, that is, the light detection groove 7 is slightly shifted to the equipment center 14 side. By attaching the PD element 91 at the position, it becomes possible to detect with high sensitivity. At this time, the output of the leakage light of the communication light in the 1.5 μm wavelength band is larger than the case where the leakage light of the communication light in the 1.3 μm wavelength band is directly above the light detection groove 7 at the position where the maximum output is. Get smaller. Therefore, by using the mounting position of the PD element 91 and the filter means 300 together, the leakage light of the communication light in the desired 1.3 μm wavelength band is received with high sensitivity (1.5 μm wavelength incident on the wavelength selection filter 93). S / N can be improved by reducing the band communication light.

  If the communication light detector cannot detect communication light in the 1.3 μm wavelength band from the user's home, it can be determined that the line is not being used.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  An example of the configuration of the light leakage portion is described in Japanese Patent Application Laid-Open No. 2009-276627. For example, the ferrules 104c and 104y of the optical connector in which both end portions in the longitudinal direction of the light detection joined body 2 incorporate optical fibers 106C and 106y, respectively. However, the communication light leaks at the joined portion, and the light leaking portion 16 is formed. In particular, when the structural parameters of the optical fiber 4 of the optical sensing joint 2 are different from the structural parameters of the optical fibers 106c and 106y, or when the optical axes of the optical fiber 4 and the optical fibers 106c and 106y of the optical sensing joint 2 are slightly shifted. Since the intensity of the leaked light at the joint becomes strong, the leaked light from the light leaking part can be detected by the light detecting part 9, and the light detecting groove 7 or the refractive index matching agent r is used. Communication light can be detected.

  In addition, as the wavelength selection filter 93, one type of wavelength selection filter having the characteristics of 1.3 μm wavelength band transmission / 1.5 μm wavelength band cut-off is used, but further 1.3 μm wavelength band transmission is performed so as to reflect obliquely incident light. A wavelength selective filter having a /1.6 μm wavelength band cutoff characteristic can also be combined to provide a large number of wavelength transmission / cutoff characteristics. That is, the filter means may be composed of a combination of a flat plate with holes and a plurality of types of wavelength selection filters, or may be composed of only a combination of a plurality of types of wavelength filters.

  Further, the filter means 300 is formed so as to be detachable from the PD 90, and is attached to the communication optical transmission line with the filter means 300 attached, and after detecting that there is no communication light in the 1.3 μm wavelength band, the filter means 300 It is confirmed whether the line from the equipment center 14 side to the communication light detector is normal or abnormal (disconnected) by detecting the presence or absence of communication light in the 1.5μm wavelength band by attaching it to the communication light transmission line with the cable removed. Will be able to.

  The present invention is applicable not only when propagating different communication lights from both ends of the communication light detector, but also when transmitting communication light having different wavelengths from one end of the communication light detector at the same time. is there.

  DESCRIPTION OF SYMBOLS 1 ... Communication light detector, 2 ... Light detection joined body, 7 ... Light detection groove | channel, 9 ... Light detection part, 13 ... Communication light transmission path, 92 ... Flat plate with a hole part, 93 ... Wavelength selection filter, 300 ... Filter Means, r ... refractive index matching agent.

Claims (7)

A communication light transmission path through which a plurality of communication lights having different wavelengths are propagated, a light leakage part formed in the communication light transmission line, and a desired wavelength among the plurality of communication lights having different wavelengths leaking from the light leakage part Filter means for transmitting communication light having a wavelength and absorbing or reflecting communication light having an undesired wavelength;
A light detection unit for detecting communication light having the desired wavelength transmitted by the filter means;
A communication light detector comprising:   The light leakage part is composed of a light detection groove that penetrates the core of the communication light transmission path of the light detection bonded body and a refractive index matching agent that is filled in the light detection groove. The communication light detector as described.   The communication light detector according to claim 1, wherein the light leakage portion is configured by a joint portion between both ends in the longitudinal direction of the light detection joined body and an optical fiber built in an optical connector joined to both ends. .   The light leakage part is composed of both ends in the longitudinal direction of the light detection joined body and a joint part between the optical fibers built in the optical connectors joined to both ends, and the optical fiber inside the light detection joined body is a communication optical transmission line. The communication light detector according to claim 1, wherein the communication light detector is different from a structural parameter of an optical fiber forming the optical fiber. The filter means comprises a flat plate with a hole and a wavelength selection filter,
The plurality of communication lights having different wavelengths leaking from the light leaking part are incident on the wavelength selection filter through the hole part of the flat plate with the hole part,
The flat plate with a hole transmits vertically incident light incident perpendicularly or substantially perpendicularly to the wavelength selection filter among a plurality of communication lights having different wavelengths leaking from the light leakage portion,
The communication light detector according to claim 4, wherein the wavelength selection filter transmits communication light having a desired wavelength out of the normal incident light and reflects communication light having an undesired wavelength. .   The communication light detector according to claim 5, wherein the flat plate with a hole has a black paint applied to a bottom surface and an inner wall surface thereof or is formed of a black resin. The communication light propagating in the communication light transmission path is communication light consisting of a 1.3 μm wavelength band and a 1.5 μm wavelength band,
The communication light detector according to claim 1, wherein the wavelength selection filter has a characteristic of transmitting a 1.3 μm wavelength band and reflecting a 1.5 μm wavelength band.

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