JP2004325334A - Method of identifying optical fiber, and light-receiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an method of identifying optical fiber which not only identifies optical fibers, but also specifies the transmitting direction of signal light of the identified optical fibers. <P>SOLUTION: A curved part is formed in an optical fiber to be identified (1), and leakage light leaking from the curved part is detected by a light-receiving apparatus (4) to identify the optical fiber. A light-receiving element of the light receiving apparatus (4) has such a diaphragm as to specify a light-receiving area so that output is, according to the transmitting direction of identifying light. The leakage light is detected in a first detection process. When the leakage light is detected, an optical fiber to be distinguished is specified. The orientation of the light-receiving apparatus is reversed to detect leakage light in a second detection process. Then the intensity of the leaking light in the first detection process is compared with the intensity of the leaking light in the second detection process. Depending on the result of the comparison, the transmission direction of signal light traveling from a station toward a subscriber is specified. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
In the construction and maintenance of an optical fiber communication network, the present invention provides an optical fiber control method for specifying an optical fiber in order to avoid erroneous disconnection or incorrect connection of the optical fiber, particularly, in addition to the optical fiber control, a subscriber from a station. The present invention relates to an optical fiber contrast method that can also determine the direction in which signal light propagates from a home or a station to another station.
[0002]
[Prior art]
In the construction and maintenance of the optical fiber communication network, it is necessary to individually identify the optical fiber in the optical fiber cable or at the subscriber's house at the work site in order to prevent a situation such as erroneous disconnection or erroneous connection of the optical fiber 1. . This operation is called an optical fiber control, and is usually performed by a method as shown in FIG. That is, from a control optical signal light source device (hereinafter, referred to as a "light source device") 2 installed on the upstream side (the left side in FIG. 1 corresponds to the direction from the subscriber's home to the office) of the optical fiber 1 requiring the control. A control light signal (hereinafter, referred to as “control light”) is made incident on the optical fiber 1 via a control light signal incident device (hereinafter, referred to as “incident device”) 3. On the downstream side of the optical fiber 1 (the right side in FIG. 1 corresponds to the direction from the station to the subscriber's house), the optical fiber 1 is bent into the optical fiber 1 by using a reference optical signal light receiving device (hereinafter referred to as “light receiving device”) 4. , The control light is leaked or emitted out of the optical fiber core 1, and the emitted leaked light is detected.
[0003]
Here, the light source device 2 emits 270 Hz light such as a laser diode (LD) or a light emitting diode (LED) having a longer wavelength than a communication optical signal (hereinafter referred to as “communication light”) for providing information or the like to a subscriber's house. This is a device that emits signal light with frequency modulation. For example, when the wavelength of the communication light is 1.31 μm, the wavelength of the reference light is 1.55 μm, and when the wavelength of the communication light is 1.55 μm, the wavelength of the reference light is 1.65 μm. Further, as the incident device 3, the control light is directly incident from an optical fiber coupler, a waveguide type directional coupler, or an upper end face of the optical fiber 1. In addition, the light receiving device 4 is provided with a bending mechanism for efficiently radiating only the reference light out of the optical fiber 1 while suppressing the loss of the communication light to a predetermined level. A light signal receiving element (hereinafter referred to as a "light receiving element") such as a Ge photodiode or an InGaAs photodiode for receiving the emitted light is provided to determine the presence or absence of the reference light and to measure the intensity. Can be.
With such a configuration, even during transmission / reception of communication light, an operator on the lower side detects the reference light incident from the upper side of the optical fiber 1 using the light receiving device 4 so that the optical fiber contrast is performed. Is done. (For example, see Non-Patent Document 1)
[0004]
[Non-patent document 1]
Enomoto et al .: "Design of a compact optical fiber ID tester using a hybrid optical module", Proc. Of the 1996 IEICE Communications Society Conference (volume: Communication 2), Lecture No. B-976, p. 461
[0005]
[Problems to be solved by the invention]
In the star network, which had been the mainstream in the dawn of optical service demands where the amount of optical fiber cable equipment was small, it was possible to visually identify the upper and lower portions of the optical line. However, in a loop network, which is one of the wiring forms for responding to an increasing demand for optical services, the upstream and downstream sides of the optical line cannot be specified because the cutting position of the optical fiber 1 is determined in detail. However, there is a risk that the optical fiber 1 may be cut at an incorrect position. Therefore, if the upstream side or the downstream side can be specified in addition to the control of the optical fiber, the advantage that the risk of erroneous operation can be avoided is achieved. However, the curved shape given to the optical fiber 1 by the conventionally used light receiving device 4 is symmetrical on the upstream side and the downstream side as shown in FIG. 2, and the control optical signal is guided to the light receiving element. Since the position of the center line of the waveguide and the center line of the light receiving element were the same, control light was incident from either the upstream side (left side in FIG. 1) or the downstream side (right side in FIG. 1) of the optical fiber 1. Also, since the same measured value was obtained in the measurement of the intensity of the reference light, it was not possible to determine the traveling direction of the control optical signal, that is, the upper and lower portions of the optical line, with one light receiving element. Further, there is a problem that the method of determining the upstream or downstream of the optical line using two light receiving elements is costly.
[0006]
Therefore, the present invention has been made in view of the above circumstances, and in addition to the optical fiber contrast, the traveling direction of the optical signal for comparison, that is, an optical fiber contrast method that can reliably determine the upstream or downstream of the optical line. Is provided.
Still another object of the present invention is to provide an optical fiber contrast method capable of simultaneously specifying an optical fiber contrast and a propagation direction of an optical signal using an inexpensive measuring device without using a plurality of light receiving elements.
[0007]
[Means for Solving the Problems]
The optical fiber contrast method according to the present invention comprises an optical fiber laid or to be laid between a station accommodating a plurality of optical fibers and a subscriber house accommodated by the station or between a station and another station. A core wire contrast method for identifying, using a light source device arranged on the station side and a light receiving device arranged downstream from the station, optically coupled to the optical fiber to identify the light source device In the method of contrasting the optical fiber cord to identify the optical fiber by projecting the control light and detecting the light leaked from the optical fiber by the light receiving device,
As the light receiving device, a light receiving device main body having an optical fiber guide portion for bending an optical fiber to be contrasted into a substantially arc shape, and a single light receiving surface disposed so as to face the optical fiber guide portion of the light receiving device main body. A light-receiving element that receives light leaking from the optical fiber, and a diaphragm that is located between the optical fiber guide and the light-receiving element and regulates light incident on the light-receiving element, wherein the optical fiber guide is A first end, a second end opposite to the first end, and a substantially arc-shaped curved portion located between the first end and the second end; The light receiving element and the stop are arranged so as to face a peak portion of the arcuate curved portion, and the shape of the stop is substantially orthogonal to a plane including a center line passing through the center of the curved portion and including the optical fiber guide. When the light receiving surface of the light receiving element is divided into two Using a defined light receiving device to be larger than the light receiving area of the light receiving area and the other side of the one side,
Optically coupling the light source device to an optical fiber to be identified, and mounting an optical fiber to be contrasted to the light receiving device;
A first detection step of projecting identification light from the light source device to the optical fiber and detecting light leaking from the optical fiber by the light receiving device,
When leakage light is detected, a second detection step of detecting the leakage light again with the mounting direction of the light receiving device being opposite to the optical fiber,
Comparing the intensity of the leakage light detected in the first detection step with the intensity of the leakage light detected in the second detection step;
Based on the comparison result, the identification of the optical fiber and the propagation direction of the optical signal transmitted from the station of the identified optical fiber to the subscriber home or from the station to another station are specified.
[0008]
First, in this specification, as the definitions of the upstream side and the downstream side, the optical line between the station and the subscriber's house is defined as the station side as the upstream side and the subscriber's house side as the downstream side. Also, between a specific station and another station, the specific station side is the upstream side and the other station side is the downstream side. The present inventor has conducted various experiments and analyzes on leaked light leaked or emitted from the curved portion of the optical fiber, and as a result, it has been found that an intensity distribution occurs along the propagation direction of the optical signal. That is, when the reference light propagates through the curved portion, if the control light exceeds the critical angle, the control light is emitted from the optical fiber to the outside. In this case, the emitted light travels from the peak position of the curved portion toward the downstream side. Therefore, a large amount of outgoing light reaches a portion located downstream of the peak position of the curved portion, and a small amount of leakage light enters a portion located upstream of the peak position. In this case, by using two light receiving elements and arranging one light receiving element on the upstream side and the other light receiving element on the downstream side with the peak position of the curved portion interposed therebetween, and detecting the difference in the amount of incident light, It can be determined which side of the optical fiber is upstream or downstream. However, if the determination is performed using a plurality of light receiving elements, there is a disadvantage that the measuring device becomes expensive.
[0009]
Therefore, in the present invention, the propagation direction of the signal light is specified using one light receiving element. In the present invention, the light receiving area of the light receiving surface of one light receiving element is different between the upstream side and the downstream side. The light receiving element is arranged so as to face the peak portion, and the light receiving area on one side is increased while the light receiving area on the other side is reduced with the peak portion interposed therebetween. In contrast to the optical fiber, the mounting direction of the light receiving device is reversed with respect to the optical fiber to be identified, and the leaked light is detected twice. In this case, when the side having the larger light receiving area with respect to the traveling direction of the reference light is located downstream in the propagation direction of the reference light, a relatively large output signal is generated from the light receiving element, while the side having the smaller light receiving area is located on the upstream side. , A small output signal is generated from the light receiving element. Therefore, the propagation direction of the control light can be specified only by reversing the mounting direction of the light receiving device and performing measurement twice. For example, in the detection step in which high-intensity leaked light is detected, the side having the larger light receiving area is downstream. Side. As described above, according to the present invention, it is possible not only to control or discriminate a large number of optical fibers, to control a specific optical fiber, but also to specify the propagation direction of the signal light using an inexpensive detector. As a result, it is possible to reliably determine the directionality of the reference light, and to identify not only the corresponding optical fiber but also the upstream and downstream of the optical line for determining the cutting position of the optical fiber in detail. Therefore, erroneous cutting of the optical fiber can be prevented.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 3 is a diagram showing an overall configuration of a system in which the optical fiber contrast method according to the present invention is performed. In this example, an example will be described in which an optical fiber laid between a station and a subscriber's house is compared. The optical fiber to be contrasted is designated by the reference numeral 1, one end of which is housed in the office (left side in the drawing) and the other end (right side in the drawing) is connected to the subscriber's home. The station contains a large number of optical fibers, of which one optical fiber 1 is compared or identified at a position along the optical line. The light source device 2 is arranged at or near a station. The light source device 2 is optically coupled to the optical fiber 1 by an incident device (coupler) 3, and reference light generated from the light source device propagates through the incident device 3 toward the optical fiber 1 toward the subscriber's home. At a work position on the way to the subscriber's house, the optical fiber 1 is specified from a large number of optical fibers using the light receiving device 4 by contrast work. This contrasting operation is performed by detecting light leaking or leaking from the optical fiber 1 in the light receiving device. For example, one optical fiber is taken out from a large number of optical fibers and attached to the light receiving device 4, and the leaked light is detected. The optical fiber specified by the station in advance is identified based on whether or not the optical fiber is detected. If no leak light is detected, another optical fiber is attached to the light receiving device, and the leak light is detected.
[0011]
4A and 4B show an example of a light receiving device according to the present invention. FIG. 4A is a perspective view showing the entire structure, FIG. 4B is a bottom view, and FIG. 4C is a side view. It is. The light receiving device 4 has a block-shaped light receiving device main body 10, and the light receiving device main body 10 has an optical fiber guide portion 11 for bending an optical fiber to be identified into a substantially arc shape. This optical fiber guide portion holds the optical fiber and forms a substantially arcuate curved portion on the optical fiber to be identified when detecting leaked light from the optical fiber. It consists of an open curved groove. Therefore, the optical fiber to be controlled can be mounted by fitting the optical fiber to be controlled into the curved groove. The optical fiber guide has a first end 11a on one side and a second end 11b on the opposite side. A substantially arc-shaped curved portion 11c is provided between the first end and the second end. The radius of curvature of the arcuate curved portion 11c is set to a value at which the reference light propagating through the optical fiber exceeds the critical angle and exits or leaks from the optical fiber to the outside. The most protruding portion 11d of the arcuate curved portion is referred to as a peak portion.
[0012]
As shown in FIGS. 4B and 4C, a light receiving element 12 for detecting leakage light is disposed at a position facing the peak portion 11d. An opening 13 is formed in the light receiving device body 10 in a region between the peak portion 11d of the optical fiber guide and the light receiving element 12, and the light incident on the light receiving element 12 is restricted by the opening 13. In this example, the positioning is performed so that the axis passing through the peak portion 11d of the curved portion 11c and the axis passing through the center of the light receiving surface of the light receiving element coincide with each other. Therefore, the aperture 13 functions as a stop that regulates the light receiving area of the light receiving element 12.
[0013]
FIG. 5 is a diagram showing the shape of the aperture, that is, the shape of the stop 13. In the present invention, when the shape of the aperture or the aperture 13 is divided into two by the surface including the axis passing through the peak portion of the curved portion and orthogonal to the surface including the optical fiber guide portion 11, one side is formed. Is set to be larger than the light receiving area on the other side. FIG. 5A shows an example in which the shape of the opening is pentagonal, FIG. 5B shows an example in which the opening is trapezoidal, and FIG. 5C shows an example in which the opening is triangular. By setting the shape of the opening 13 in this way, the light receiving area of the light receiving element 12 is large in the right region of the drawing and small in the left region. In this case, in FIG. 5, when the reference light travels from the left to the right, the light receiving element 12 receives a larger amount of leaked light and generates a larger output signal. On the other hand, when the control light travels from the right to the left in FIG. 5, the leakage light from the optical fiber is limited by the aperture 13, so that a small amount of leakage light enters the light receiving element 12 and A small output signal is generated. Accordingly, the direction of the reference light can be specified by reversing the direction of the light receiving device with respect to the optical fiber, detecting the leaked light twice, and comparing the output signals from the light receiving elements.
[0014]
Next, an algorithm for specifying the reference of the optical fiber and the propagation direction of the signal light at the work site will be described. FIG. 6 is a flowchart describing an algorithm for specifying the control direction of the optical fiber and the propagation direction of the signal light according to the present invention.
[Step 1]
At the work site, one optical fiber to be identified is selected from a large number of optical fibers and attached to the light receiving device. At the work site, since it is impossible to determine which side of the optical fiber is the office side, the direction of the light receiving device, that is, the direction in which, for example, high leakage light intensity is detected (ie, the direction toward the side having a large light receiving area with respect to leakage light) when mounting the optical fiber. Is set as the first direction, and the direction in which the weak leakage light intensity is detected is set in advance as the second direction. In this case, the first direction is the downstream side (the direction in which the signal light from the station travels).
[Step 2]
Next, a first leaked light detection step is performed. The control light is projected onto a specific optical fiber to be identified from the light source device arranged on the station side, and the leak light is detected by the light receiving element of the light receiving device. If no leakage light is detected, the process returns to step 1 and another optical fiber is selected and mounted on the light receiving device. On the other hand, when the leaked light is detected, the optical fiber is determined to be the optical fiber to be identified, and the process proceeds to the next step 3.
[Step 3]
In step 3, a second leaked light detection step is performed. That is, leakage light is detected by reversing the mounting direction of the light receiving device for the optical fiber.
[Step 4]
Next, the leak light intensity detected in the first leak light detecting step is compared with the leak light intensity detected in the second leak light detecting step measured in the opposite direction. As a result of the comparison, the direction of the light receiving device in the detection step in which high leakage light intensity is detected is determined to be downstream. Alternatively, it is determined that the second direction of the light receiving device in the detecting step in which the weak leakage light intensity is detected is downstream.
[0015]
The present invention is not limited to the embodiments described above, and various modifications and changes are possible. For example, in the above-described embodiment, an example in which the light source device is arranged in the office or in the vicinity thereof and the optical fiber is compared in the middle of the optical line has been described. Of course, the light source device is installed on the subscriber home side or another office side. It is also possible to arrange and perform optical fiber contrast.
Further, in the above-described embodiment, an example is described in which the optical line between the station accommodating a plurality of subscribers and the subscriber home accommodated in the station is compared or identified. The present invention can also be applied to a case where an optical fiber contrast is performed in the optical path between the optical fiber and the optical fiber.
Furthermore, as an optical fiber to be compared, a single optical fiber, an optical fiber tape, or an optical fiber cord can be a control object.
Further, as an aperture defining the light receiving area of the light receiving element, an aperture is formed in the light receiving device main body to constitute the aperture, but an aperture may be provided as another member.
[0016]
【The invention's effect】
As described above, according to the present invention, the traveling direction of the reference light, that is, the upper and lower portions of the optical line can be reliably determined at a low cost (one light receiving element), and the relevant optical fiber can be specified, Since the cutting position of the optical fiber can be determined in detail, there is an effect that erroneous cutting of the optical fiber can be prevented.
Therefore, it is possible to greatly contribute to the reduction of the construction operation and the improvement of the reliability of the optical communication service in the future.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a conventional optical fiber contrast method.
FIG. 2 is a diagram showing a conventional light receiving device.
FIG. 3 is a diagram showing an overall system for implementing an optical fiber contrast method according to the present invention.
FIG. 4 is a diagram showing an example of a light receiving device according to the present invention.
FIG. 5 is a diagram illustrating various examples of openings according to the present invention.
FIG. 6 is a flowchart illustrating an algorithm of an optical fiber contrast method according to the present invention;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 optical fiber 2 reference optical signal light source device 3 reference optical signal incident device 4 light receiving device 10 light receiving device main body 11 optical fiber guide section 12 light receiving element 13 aperture (aperture)

Claims (9)

Optical fiber contrast method for identifying an optical fiber laid or to be laid between a station accommodating a plurality of optical fibers and a subscriber house accommodated by the station or between the station and another station. Using a light source device arranged on the station side and a light receiving device arranged downstream from the station, optically couples the light source device to an optical fiber to be identified and projects control light, In an optical fiber contrast method for identifying an optical fiber by detecting light leaked from the optical fiber by the light receiving device,
As the light receiving device, a light receiving device main body having an optical fiber guide portion for bending an optical fiber to be contrasted into a substantially arc shape, and a single light receiving surface disposed so as to face the optical fiber guide portion of the light receiving device main body. A light-receiving element that detects light leaking from the optical fiber, and a diaphragm that is located between the optical fiber guide and the light-receiving element and that regulates light incident on the light-receiving element, the optical fiber guide is provided with: A first end, a second end opposite to the first end, and a substantially arc-shaped curved portion located between the first end and the second end; The light receiving element and the stop are arranged so as to face a peak portion of the arcuate curved portion, and the shape of the stop is substantially orthogonal to a plane including a center line passing through the center of the curved portion and including the optical fiber guide. When the light receiving surface of the light receiving element is divided into two Using a defined light receiving device to be larger than the light receiving area of the light receiving area and the other side of the one side,
Optically coupling the light source device to an optical fiber to be identified, and mounting an optical fiber to be contrasted to the light receiving device;
A first detection step of projecting control light from the light source device to the optical fiber and detecting light leaking from the optical fiber by the light receiving device,
When leakage light is detected, a second detection step of detecting the leakage light again with the mounting direction of the light receiving device being opposite to the optical fiber,
Comparing the intensity of the leakage light detected in the first detection step with the intensity of the leakage light detected in the second detection step;
An optical fiber contrast method comprising: identifying an optical fiber based on the comparison result and specifying a propagation direction of an optical signal transmitted from a station of the identified optical fiber to a subscriber home or from a station to another station. . 2. The optical fiber contrast method according to claim 1, wherein the light source device is disposed at or near a station, and the light receiving device is located at an intermediate position between the station and a subscriber's house or between a station and another station. Characterized in that the optical fiber is located at an intermediate position of the optical fiber and the propagation direction of the optical signal transmitted from the station is specified. 3. The optical fiber contrast method according to claim 2, wherein, in a leakage light detection step in which a higher leakage light intensity is detected, an extending direction of the optical fiber facing a side having a larger light receiving area of the light receiving element is determined to be a downstream side. An optical fiber contrast method. 3. The optical fiber contrast method according to claim 2, wherein in the leakage light detection step in which a weaker leakage light intensity is detected, it is determined that the extending direction of the optical fiber facing the side where the light receiving area of the light receiving element is smaller is the downstream side. An optical fiber contrast method. 5. The optical fiber contrast method according to claim 1, wherein if no leakage light is detected in the first leakage light detection step, leakage light detection processing is performed on another optical fiber. 6. An optical fiber contrast method, comprising: A light receiving device used in an optical fiber contrast method for identifying a specific optical fiber from a plurality of optical fibers,
A light receiving device main body having an optical fiber guide portion for bending an optical fiber to be compared into a substantially arc shape, and a light receiving element having a single light receiving surface, which is disposed so as to face the optical fiber guide portion of the light receiving device main body. A stop located between the optical fiber guide and the light receiving element, and a stop for regulating the light receiving area of the light receiving element,
The optical fiber guide includes a first end and a second end opposite to the first end, and a substantially circle located between the first end and the second end. It has an arcuate curved part,
The light receiving element and the stop are disposed so as to face a peak portion of the arcuate curved portion, and the shape of the stop includes a center line passing through the center of the curved portion, and is substantially orthogonal to a plane including the optical fiber guide. A light receiving device characterized in that, when the light receiving surface of the light receiving element is divided into two parts, the light receiving area on one side is larger than the light receiving area on the other side. 7. The light receiving device according to claim 6, wherein the light receiving device main body has an opening at a position facing the arcuate curved portion of the optical fiber guide, and the opening forms the stop. Light receiving device. 7. The light-receiving device according to claim 6, wherein an opening is provided at a portion of the optical fiber guide of the light-receiving device main body, the opening facing a peak portion of the arcuate curved portion, and a specific portion is provided between the opening and the light-receiving element. A light-receiving device comprising a stop having an aperture shape. 9. The light receiving device according to claim 6, wherein said stop has a triangular, pentagonal or trapezoidal shape.

Images