JP3078104B2 - Optical line identification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for identifying an optical line used for optical communication at an end thereof.

[0002]

2. Description of the Related Art As a method for identifying an optical line, the refractive index of a core of the optical line is partially changed, and the position of this change is designated as OTDR.
A method of detecting at the end of a line using a measuring method is known (The 1991 Autumn Meeting of the Institute of Electronics, Information and Communication Engineers, Document B-59).
1 "Remote fiber identification method for optical line database").

[0003]

However, according to this method, the identification code portion provided on the optical line extends over several hundred meters. For example, in the example in the above-mentioned document, recording an 8-bit identification code on an optical line requires 50 m per bit and a total length of 400 m. Therefore, it is difficult to attach an identification code to an optical line having a short length. Also, in order to record an identification code over several hundred meters on an optical line, this must be performed during the manufacturing process of the optical line, which is not practical.

[0004]

In order to solve such a problem, an identification method according to the present invention provides a plurality of reflectors for reflecting light of a specific wavelength only on an optical line, and for each optical line. The combination of the specific wavelength of the reflector and the reflectance is used as an identification marker, and the wavelength and light intensity of the reflected light from the identification marker when the inspection light is incident on these optical lines are measured. Is used to identify the optical path.

[0005] Instead of providing the identification mark directly in the optical line, a branch line having the identification mark may be added to the optical line.

[0006]

When the inspection light is incident from one end of the optical line, the light is reflected by the reflecting portion, which is an identification mark, and returns to the incident end.
If the wavelength of the reflected light and the reflectivity of the reflecting portion are made different for each optical line, and the wavelength and the light intensity of the reflected light are measured, the optical line can be identified from the measurement result.

[0007]

FIG. 1 is a configuration diagram showing an optical line facility management system to which an optical line identification method according to the present invention is applied. Office building 1
A terminal box 2 for switching connection of an optical line is provided between the terminal box 2 and the subscriber home 3. A plurality of optical lines, one ends of which are connected to the transmission device 4 in the office 1, are bundled as an optical fiber cable 9 and extend to the terminal box 2. The other end of each optical line is connected to one end of the optical line extending to each subscriber's home 3 via an optical connector 10 in the terminal box 2, whereby the transmission device 4 in the office building 1 is connected to each end. This means that each of the subscriber homes 3 is connected by one optical line.

In the optical connector 10, the connection can be manually switched arbitrarily. When this switching is performed, first, the identification information reading device (code reading device) 5 placed in the station building 1 checks the route information of the optical line by an identification method described later, and the route information is checked by the control device 6. To the local controller 11 in the terminal box 2, and the display device 12 notifies the worker at the site of the information. The operator performs desired connector switching based on the route information. After the switching work is completed, the code reader 5 reads the identification mark of the optical path again, confirms the route information on the side of the station 1, and displays this route information on the display device 12 from the control device 6 via the local controller 11. Thus, the operator confirms whether or not the switching has been performed.

FIG. 2 is a block diagram showing the internal configuration of the code reading device 5 and its peripheral devices. The code reading device 5 includes a light emitting unit 20 and a light receiving unit 21. The operation of these units is controlled by a computer 22 and a timing control circuit 23 that constitute the control circuit 6.

The light emitting section 20 includes a light source 24 that emits light having an appropriate spectral width such as white light, an acousto-optic element 25 that controls on / off of light emitted from the light source 24, and an input / output of the acousto-optic element 25. The light emitted from the light source 24 is transmitted through the lens 26, the acousto-optic device 25, and the lens 27.
, And is incident on one end of the optical fiber 40 as inspection light. The optical fiber 40 is a branch optical line that connects the optical fiber 50, which is a measured optical line, and the code reading device 5, and is connected to the measured optical line 50 via the connection unit 38. The connection means 38 is for selectively connecting the optical fiber 40 to any one of a number of optical paths 50 to be measured.

The light receiving section 21 includes a Fabry-Perot etalon 32, which is an interference spectroscope, and an etalon controller 33 for controlling a distance between two resonance flat plates in the etalon 32.
And a lens system 3 provided in the input / output unit of the etalon 32
0, 31, a light receiving element 34 for converting the light intensity of the output light of the etalon 32 into an electric signal, and a box car integrator 35 for temporally cutting out the output signal of the light receiving element 34 by a signal from the timing control circuit 23. A / D for converting the output signal of the boxcar integrator 35 into a digital signal
And a conversion circuit 36. The etalon 32 receives light from the optical fiber 41 connected to the optical fiber 40 by the optical fiber coupler 37, and performs the light separation.
At that time, the etalon controller 33 changes the spectral wavelength by controlling the interval between the resonance surfaces in the etalon 32 based on a command from the computer 22. Computer 22
By taking in the data from the A / D conversion circuit 36 while controlling the etalon 32, the wavelength analysis of the reflected light can be performed.

Each optical line 50 has a unique identification mark (code) 39 written in the line. The identification marker 39 is provided with a plurality of reflective portions that reflect light of a specific wavelength only, and changes the combination of the specific wavelength and the reflectance of the reflective portion for each optical path. Each of the reflection portions constituting the identification mark 39 is configured by a stripe in which the refractive index of the optical line 50 is locally changed, and by appropriately setting the spatial frequency of the refractive index change, the value of the refractive index, and the like, It is possible to obtain the reflected light wavelength and the reflectance specific to the reflecting portion. FIG.
As shown in (a), the reflection part 100 is formed on the optical line 50 with stripes in which the refractive index is changed at a constant period. Assuming that the period of the stripe 100 (the interval between adjacent refractive index change points) is d and the average refractive index of the optical line in the reflecting section is n, the reflected light wavelength λ is λ
= 2nd, a desired reflected light wavelength can be obtained by appropriately setting d and n. Also,
As for the reflectance, a desired value can be obtained by adjusting the number of stripes or the difference in refractive index. The reflection section 100 obtained in this way is connected to the optical line 50 as shown in FIG.
A plurality of parts (five places in the figure) are provided on the
The reflected light wavelengths [lambda] 1 to [lambda] 5 and the values of their reflectivities are appropriately set as the identification mark 39. Since the refractive index can be changed by locally irradiating the UV light (ultraviolet light) to the optical line 50, a reflection portion that reflects only a desired wavelength at a desired reflectance can be formed by using this.

The identification marks 39 are provided on the optical line between the station 1 and the terminal box 2 and the optical line between the terminal box 2 and the subscriber's house 3 in FIG. When a plurality of terminal boxes are interposed between the office building 1 and the subscriber's house 3, an identification mark is also provided on the optical line between the terminal boxes.

Next, a method of reading the identification mark 39 will be described. For example, it is assumed that quaternary coding is performed using six wavelengths from λ0 to λ5 as reflection wavelengths. That is, λ0 is the reflection wavelength of the reference reflection unit, and the reflection light intensity for the other wavelengths λ1 to λ5 is made to correspond to any of “0” to “3” based on the reflection light intensity from the reference reflection unit. FIG. 4A is a characteristic diagram illustrating an example of a reflected light wavelength characteristic obtained when the inspection light is applied from the light emitting unit 20 to an arbitrary optical line 50. In this characteristic diagram, the horizontal axis represents wavelength, and the vertical axis represents light intensity. In this example, the reflected light intensity for each of the reflection wavelengths λ1 to λ5 is “a, 0, 3a, 0, 2a” with respect to the reflected light intensity a from the reference reflection unit.
FIG. 6B shows the result of the observation in association with the code information. That is, from the observation result of FIG.
302 "can be obtained.

In this embodiment, the optical line connecting the office 1 and the subscriber's house 3 is composed of two sectioned optical lines connected by a terminal box 2. Since the identification signs are provided on each of the divided optical lines, it is necessary to distinguish and recognize these. The boxcar integrator 35 is used for that purpose. That is, the timing control circuit 23 causes the pulse-like inspection light to be incident on the optical path to be measured, and temporally cuts out the reflected light for each identification marker based on the incident timing of the inspection light. As a result, it is possible to distinguish reflected light from identification marks at different points on the same optical path. The computer 22 can measure the reflected light spectrum for each identification mark by taking in the light intensity data for each wavelength while distinguishing the reflected light for each identification mark. The cut-out of the reflected light can also be achieved by using an optical gate (optical deflector) instead of the boxcar integrator 35.

As shown in FIG. 5, instead of directly writing the identification mark in the optical line, a branch optical line 101 on which the identification mark 100 is written may be added using a fiber coupler 102 or the like.

In the above embodiment, the white light source 24 is used as the light source, and the Fabry-Perot etalon 32, which is a spectroscope, is used for the light receiving unit 21. However, as shown in FIG. By using the light source 109, the spectroscope of the light receiving unit 21 can be omitted. The light source 109 is
The semiconductor laser array 110, the prism 113, and the condenser lens 27 are incorporated. Semiconductor laser array 110
Are a plurality of semiconductor lasers 111 having different oscillation wavelengths
And a lens 112 provided for each semiconductor laser 111
It has. The control circuit 114 controls the semiconductor laser 111
, And control of the movement of the prism 113, whereby the light source 109 can selectively emit inspection light of a specific wavelength. The reflected light wavelength of each reflecting portion of the identification marker 39 is selected from among the oscillation wavelengths of the semiconductor laser 111. Therefore, when identification is performed, the wavelength of the inspection light is sequentially switched and emitted, and if the presence or absence of reflected light is detected for each wavelength, the reflected light of the reflective portion forming the identification marker is detected as in the above-described embodiment. You can know the wavelength. In this example, the boxcar integrator 35 is operated based on the timing signal from the control circuit 114 in order to temporally cut out the reflected light, but a light receiving element is provided at the other end of the optical fiber 41. The detection timing of the inspection light may be detected, and this detection signal may be used as an operation timing signal for the boxcar integrator 35.

FIG. 7 is a partially cutaway perspective view showing another example of the configuration of the reflecting portion used as the identification mark 39. In this example, an optical filter is used as a reflection unit that reflects only a specific wavelength. A method of forming the identification mark will be briefly described. Two V-grooves 201, 20 are formed on a silicon substrate 200.
2 are formed, and the optical fibers 204 and 205 of the two-core tape fiber 203, which are optical lines, are embedded in each of them. After that, the optical fibers 204 and 205 are fixed by covering with a silicon lid 206 from above and hardening with a resin 207. Next, a groove 208 is formed in the silicon substrate 200 from above the silicon lid 206.
Is formed, the optical fibers 204 and 205 are cut. Then, by fitting a desired monochromatic reflected light filter 210 into the groove 208, a reflecting portion that reflects only a specific wavelength is formed in the optical path. By providing such a reflection portion at a plurality of locations and making each of the specific wavelength and the reflectance different, the identification mark can be obtained. The optical filter 210 is composed of, for example, a dielectric multilayer film. Using this optical filter method, when the optical line is a two-core tape fiber or a multi-core tape fiber as in this example, the same identification mark can be provided to each optical fiber at the same time. is there.

FIG. 8 is a perspective view showing an example in which an optical filter is provided on a connector. In this example, an optical filter, which is an identification mark, is provided on the end face of the connector to facilitate its attachment. The connector is a guide pin 221
And a female connector 223 having a receiving hole 222 for the guide pin 221. Each of the connectors 220 and 223 has a structure in which two silicon chips 224 and 225 are stacked and fixed with an epoxy resin 226. The silicon chip 224 has the same number or more of V as the optical fibers constituting the tape fiber 227.
A groove 228 is formed, and each optical fiber has these V
It is fixed in the groove. Receiving hole 22 for guide pin 221
2 so that the optical fiber on the male connector 220 side and the optical fiber on the female connector 223 side are respectively 1
Combined one-to-one. At the time of this coupling, by interposing the monochromatic reflected light filter 230 therebetween, it is possible to form a reflection portion in the optical path, and by connecting a plurality of the reflection portions, an identification mark can be obtained. In this example, the optical filter 23
Reference numeral 0 denotes a connector separate from the connectors 220 and 223. However, a dielectric multilayer film may be formed on the end face of the female connector 223 by vapor deposition.

[0020]

As described above, according to the identification method of the present invention, the combination of the reflection light wavelengths and the reflectances of the plurality of reflection portions constituting the identification mark is set to be different for each optical path, and the reflection light By measuring the wavelength and the light intensity, the optical line can be easily and accurately identified from the measurement result. Therefore, it is very effective for confirming the connection at the time of the switching operation in the terminal box.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an optical line facility management system to which the identification method of the present invention is applied.

FIG. 2 is a block diagram showing the internal configuration of the code reading device and its peripheral devices.

FIG. 3 is a diagram showing a specific example of an identification mark.

FIG. 4 is a diagram illustrating a method of converting a reflected light spectrum into quaternary code information.

FIG. 5 is a diagram showing a branch optical line for identification signs.

FIG. 6 is a block diagram showing another configuration example of the code reading device.

FIG. 7 is a perspective view showing another example of the configuration of the reflection section constituting the identification mark.

FIG. 8 is a perspective view showing still another example of the configuration of the reflection section constituting the identification marker.

[Explanation of symbols]

1 ... office building, 2 ... terminal box, 3 ... subscriber home, 4 ... transmission device,
5 code reader, 6 controller, 20 light emitting unit, 2
1 ... light receiving section, 39 ... identification mark, 50 ... optical line.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuya Yamashita, Inventor Katsuya 1-6-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Fumio Otsuki 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Inside Telegraph and Telephone Corporation (72) Inventor Yutaka Katsuyama 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-4-84727 (JP, A) JP-A-4- 309904 (JP, A) Proceedings of the Conference of the Institute of Electronics, Information and Communication Engineers, 1991 [Autumn Season 4] (1991) p. 4.51 (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 6/00 G01M 11/00

Claims (8)

(57) [Claims] 1. A plurality of reflecting portions for reflecting light having a specific wavelength on an optical line are provided at a plurality of positions, and a specific wavelength of the reflecting portion and a combination of the reflectance thereof are changed for each optical line to form an identification marker. Measure the wavelength and light intensity of the reflected light from the identification marker when the inspection light is incident on the road,
A method for identifying an optical line based on the measurement result. 2. A branch line is added to each of the optical lines,
Reflection portions that reflect light of a specific wavelength only are provided at a plurality of locations on these branch lines, and the identification mark is changed by changing the combination of the specific wavelength and the reflectance of the reflection portion for each optical line,
A method for identifying an optical line, comprising measuring a wavelength and a light intensity of light reflected from the identification mark when inspection light is incident on the optical line, and identifying the optical line based on the measurement result. 3. A combination of a specific wavelength of the reflecting portion and a reflectance of the reflecting portion at each of a plurality of positions on the optical line for reflecting light of a specific wavelength only at each of a plurality of positions on each optical line. The identification mark is changed in turn, and when the pulse-like inspection light is incident on these optical lines, the reflection light of each reflected light that returns with a time lag depending on the position from each of the identification marks. An optical line identification method for measuring a wavelength and light intensity and identifying an optical line based on the measurement results. 4. A branch line is added at a plurality of positions on an optical line, and reflection portions for reflecting light of a specific wavelength only are provided at a plurality of positions on these branch lines. The identification mark is changed by changing the combination of the specific wavelength and its reflectance, and the pulse is returned from the identification mark when the pulse-like inspection light is incident on the optical line with a time lag depending on the position. An optical line identification method for measuring the wavelength and light intensity of each reflected light and identifying the optical line based on the measurement results. 5. The optical line identification method according to claim 3, wherein the optical line is formed by cascading a plurality of section lines, and the identification mark is provided for each of the section lines. 6. The optical line identification method according to claim 1, wherein the reflection portion is a stripe in which the refractive index of the optical line is locally changed. 7. The method for identifying an optical line according to claim 1, wherein the reflection unit is an optical filter inserted into the optical line. 8. The optical line according to claim 7, wherein the optical lines are connected by a plurality of optical connectors, and an optical filter serving as a reflecting portion is formed on an end face of each of the optical connectors. Identification method.