JPH0886717A - Light beam passage discriminating optical part and its remote control measuring method and device - Google Patents

Abstract

PURPOSE: To provide a light beam passage discriminating optical part which can be downsized without requiring a reference optical fiber, and its remote control measuring method and device. CONSTITUTION: The reflected light is obtained by sending the low coherence light to a light beam passage discriminating optical part 10 provided with a discriminating information reflecting part to display discriminating information depending on whether or not reflecting points are arranged at prescribed intervals and a reference reflecting part which is arranged at a distance longer than the total length of the discriminating information reflecting part between it and the discriminating information reflecting part and is composed of the reflecting points. This is divided into two parts in a Mach-Zehnder interferometer 50, and one is delayed to the other, and they are again put together, and the reflected light by the discriminating information reflecting part and the reflected light by the reference reflecting part are made to interfere with each other, and a change in the light intensity is detected by a detector 60, and the existence of the reflecting points in the discriminating information reflecting part, that is, the discriminating information is read.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component for identifying an optical line and a remote measuring method and device therefor.

[0002]

2. Description of the Related Art Whether or not reflection points are provided at intervals of several 100 μm in the direction of a line as a component which is provided at a predetermined position (usually the tip) of an optical line and gives identification information for identifying the optical line. There is an optical component for identifying an optical line (hereinafter, simply referred to as an optical component) that represents "1" and "0" of the identification information. As a method of remotely measuring this optical component, in other words, a method of remotely reading the identification information,
A method using a low coherence light source and a Michelson interferometer is known (for example, optics, 18 [11] (19
89) See "Interferometric Backscattering Measurement System for Optical Waveguide Evaluation").

FIG. 2 shows the above-mentioned conventional telemetry method. In the figure, 1 is a low coherence light source, 2 is a beam splitter, 3 is an optical line to be measured, and 4 is an optical line for reference light, for example. Reference optical fiber, 5 is an optical component, 6 is a movable mirror displaceable in the extension direction of the reference optical fiber 4, and 7 is a detector.

The signal light emitted from the low coherence light source 1 is split into two by the beam splitter 2, one of which enters the optical line 3 and the other of which enters the reference optical fiber 4. The signal light propagating through the optical line 3 is reflected at the reflection point of the optical component 5,
The reflected light for identification information propagates in the opposite direction through the optical line 3.
On the other hand, the signal light propagating in the reference optical fiber 4 is reflected by the movable mirror 6 and propagates in the opposite direction in the reference optical fiber 4 as reference reflected light.

The identification information reflected light and the reference reflected light are combined by the beam splitter 2. At this time, the movable mirror 6 is used.
When the optical path length of the reference reflected light that changes due to the displacement of is equal to the optical path length for the identification information reflected light from the reflection point,
Interference fringes are generated. Therefore, when the optical component 5 has a plurality of reflection points, interference fringes occur corresponding to the respective reflection points. The interference fringe is detected by the detector 7 as a change in light intensity.

Here, when an LED having a spectral width of several 10 nm is used as the low coherence light source 1, the interference fringe width is several tens of μm, and this value is the measurement resolution (the minimum interval between the reflection points that can be separately detected). ).

[0007]

However, in the above-mentioned method, the reference optical fiber corresponding to the distance from the measurement position to the installation position of the optical component, that is, the length a of the optical line is required, and the light beams of different lengths are required. In order to measure the path, it is necessary to prepare a reference optical fiber having a length accurately corresponding to each optical line and replace the reference optical fiber at each measurement, which is not practical.

When the length of the optical line reaches several kilometers, the measurement resolution deteriorates in proportion to the distance due to the influence of chromatic dispersion and polarization dispersion due to the difference between the optical line and the reference optical fiber. It is necessary to widen the arrangement interval of each reflection point in the optical component, and there is a problem that the optical component becomes large accordingly.

An object of the present invention is to provide an optical component for identifying an optical line which does not require a reference optical fiber and can be made compact, and a remote measuring method and apparatus thereof.

[0010]

In order to achieve the above object, the optical line identifying optical component according to claim 1 is provided at a predetermined position of the optical line and is provided with identification information for identifying the optical line. , Provided at a distance longer than the entire length of the identification information reflection section between the identification information reflection section and the identification information reflection section, which represents identification information depending on whether or not reflection points are provided at predetermined intervals. An optical component for identifying an optical line is proposed, which includes a reference reflection portion including the reflection points.

In a second aspect of the present invention, there is proposed the optical component for optical line identification according to the first aspect, wherein the reflection point is constituted by a slit reaching the core portion of the optical fiber.

Further, according to a third aspect of the present invention, the identification information reflection section is provided between the identification information reflection section that represents identification information depending on whether or not reflection points are provided at predetermined intervals, and the identification information reflection section. Light with low coherence is incident on an optical line provided at a predetermined position with an optical component for identifying an optical line having a reference reflection part formed of a reflection point provided at a distance longer than the entire length, and the optical line is provided. The reflected light from the identification optical component is divided into two parts, one of the two divided reflected lights is delayed, and the other reflected light is modulated and recombined, and the delay amount is referred to the identification information reflection part. A remote measuring method of an optical component for optical line identification is proposed, in which the change in the light intensity of the combined light is measured while changing the amount corresponding to the distance to the reflection part for the center.

According to a fourth aspect of the present invention, there is provided a light source for generating light of low coherence, an identification information reflecting section for indicating the identification information of the light from the light source at every predetermined interval. An optical component for identifying an optical line, which is provided with a reference reflection portion including reflection points provided at a distance longer than the entire length of the identification information reflection portion between the reflection portion for identification information, is provided at a predetermined position. A reflected light splitting unit that splits and outputs light that is incident on the provided optical line and that is output from the optical line; a first optical coupler that splits the light output from the reflected light splitting unit into two; And a Mach-Zehnder interferometer including an optical delay circuit unit that delays one light beam, a modulation circuit unit that applies phase modulation to the other divided light beam, and a second optical coupler that multiplexes the respective light beams again. , Detects the light intensity of the output light from the second optical coupler A detector, and changing the optical intensity of the output light from the second optical coupler while changing the delay amount centering on the amount corresponding to the distance between the identification information reflection unit and the reference reflection unit. We propose a remote measuring device for optical components for optical line identification.

According to a fifth aspect of the present invention, two photodetectors for converting the two output lights output from the second optical coupler into electric signals, respectively, and a difference for adding the output signals of the two photodetectors. 5. An optical component for optical line identification according to claim 4, wherein a detector comprising a dynamic amplifier and a vector signal analyzer for detecting the signal amplitude of the modulation frequency or its harmonic component in the Mach-Zehnder interferometer from the output signal of the differential amplifier is used. We propose a telemetry device.

[0015]

According to the invention of claim 1, the identification information reflecting portion can generate the identification information reflected light, and the reference reflecting portion can generate the reference reflected light. It is possible to take out the change in the light intensity representing the identification information.

According to the second aspect of the invention, the reflection point can be formed only by cutting the optical fiber.

According to the invention of claim 3, the low coherence light incident on the optical line is reflected by the identification information reflecting portion of the optical component for identifying the optical line to generate reflected light for identification information and to be referred to. The reference reflection light is generated by being reflected by the reflection portion. The reflected light including the reflected light for identification information and the reflected light for reference is divided into two, and one reflected light corresponds to the distance between the reflected portion for identification information and the reference reflective portion with respect to the other reflected light. By being delayed by the amount and combined,
One reflected light of the identification information reflected lights whose time positions match and the reference reflected light interfere with each other, and the delay amount is changed, so that each reflected light in the identification information reflected light and the reference reflected light The light and the light sequentially interfere with each other, and interference light corresponding to each reflection point in the identification information reflection section is obtained, and the identification information is extracted.

Further, according to the invention of claim 4, the low coherence light generated from the light source is incident on the optical line through the reflected light separating portion, propagates through the optical line, and reaches the optical line identifying optical component. The reflected light for the identification information propagates in the reverse direction as reflected light for the identification information in the opposite direction, and is reflected by the reference reflection portion to propagate in the reverse direction as reflected light for the reference. The reflected light including the reflected light for identification information and the reflected light for reference is separated by the reflected light separation unit, is incident on the Mach-Zehnder interferometer, and is divided into two by the first optical coupler. One of the two reflected lights is delayed by the optical delay circuit unit in an amount corresponding to the distance between the identification information reflection unit and the reference reflection unit, and the other reflected light is modulated by the modulation circuit unit. It is phase-modulated and recombined by the second optical coupler. Here, the reflected light for one of the reflected light for identification information and the reflected light for reference at the same time position interfere with each other,
By further changing the delay amount, each reflected light in the reflected light for identification information and the reflected light for reference sequentially interfere, and interference light corresponding to each reflection point in the reflection portion for identification information is obtained. At this time, the light intensity of the light output from the second optical coupler is detected by the detector, and the identification information is extracted.
Since the reflected light for identification information is phase-modulated by the modulation circuit section, only the interference component with the reflected light for reference is detected, and the background light is not detected.

Further, according to the invention of claim 5, the two output lights output from the second optical coupler, that is, the interference lights are converted into electric signals by the two photodetectors, and added by the differential amplifier. However, at this time, the noise signals cancel each other out.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of an optical component for optical line identification according to the present invention. An optical component for optical line identification (hereinafter, simply referred to as an optical component) 10 is a wavelength selection component 11 and a reflective component. 12
And a signal light A for communication by the wavelength selection component 11.
Is separated into the measurement signal light B and the influence of the reflection component 12 on the communication signal light A is suppressed.

As shown in FIG. 3, the reflective component 12 has slits formed by cutting to the core 14 of the optical fiber 13 to provide an identification information reflector 15 and a reference reflector 16.
Is formed. The reflection portion 15 for identification information is a slit 1 that forms reflection points at regular intervals of several 100 μm.
Depending on whether or not 7 is provided, "1" and "0" of the identification information of the optical line are represented. The reference reflection portion 16 is composed of a slit provided between the reference reflection portion 16 and the identification information reflection portion 15 at a distance longer than the entire length of the identification information reflection portion 15.

FIG. 4 shows the measuring principle of the remote measuring method of the present invention. The above-mentioned identification information reflecting portion 1 of the optical component 10 is described.
The reflected light E including the reflected light C for identification information by 5 and the reflected light D for reference by the reference reflection portion 16 is divided into two, and these are respectively incident on different optical paths to make one reflected light the other reflected light. By delaying and multiplexing with respect to each other, one reflected light of the reflected light C for identification information and the reflected light D for reference at the same time position are caused to interfere with each other, and further, the length of one optical path, that is, the delay. By changing the amount and sequentially causing the reflected light in the reflected light C for identification information and the reflected light D for reference to interfere with each other, each slit 17 in the reflection portion 15 for identification information of the optical component 10 is increased.
The interference light F corresponding to is obtained.

FIG. 5 shows an embodiment of an apparatus for carrying out the telemetry method of the present invention. In the figure, 10 is the above-mentioned optical component for optical line identification, 20 is a light source, 30 is a reflected light separating section, Four
0 is an optical line to be measured, 50 is a Mach-Zehnder interferometer,
60 is a detector.

The light source 20 has a short coherence length and emits light having an appropriately wide spectrum width. This light passes through the reflected light separation unit 30 composed of a fiber type optical branching component, enters the optical line 40 having the optical component 10 at its tip, and propagates this. The optical line 4 is reflected by the optical component 10
The light propagating in the reverse direction of 0 is guided to the Mach-Zehnder interferometer 50 via the reflected light separation unit 30.

The Mach-Zehnder interferometer 50 includes a first optical coupler 51 and a second optical coupler 5 as shown in FIG. 6 (a).
2, an optical delay circuit section 53, and a modulation circuit section 54 that performs phase modulation. The reflected light is an optical coupler 51.
Is divided into two equal intensity ratios, one of which is the optical delay circuit section 53.
And the other is guided to the modulation circuit section 54.

The optical delay circuit section 53 comprises a movable mirror 53a, a movable mirror mechanism section 53b, and a lens 53c used for optical coupling of the optical fiber and the movable mirror 53a. The modulation circuit unit 54 uses, for example, a single mode fiber as the piezoelectric element 54.
It is composed of a phase modulator wound around a and a polarizer 54b.

The reflected light E1 guided to the optical delay circuit section 53 gives an optical path difference such that the reference reflected light D interferes with the identification information reflected light C by the movable mirror 53a. The reflected light E2 guided to the modulation circuit unit 54 receives the piezoelectric element 54a and the polarizer 54b.
Is phase-modulated by the modulator configured by.

The light delayed by the optical delay circuit section 53 and the light modulated by the modulation circuit section 54 are combined by the optical coupler 52, and the reference reflected light D is sequentially reflected with the change of the movable mirror 53a. The light C interferes with the light C to generate an interference fringe, and the light C is divided into two equal intensity ratios.

The detector 60, as shown in FIG.
Two photo detectors 61 and 62 and a differential amplifier 63
And a vector signal analyzer 64. The divided interference light is the photodetector 6
The signals are converted into electric signals at 1 and 62, added at the differential amplifier 63, and the signal amplitude of the modulation frequency of the modulation circuit unit 54 or its harmonic component is detected by the vector signal analyzer 64. Since the reflected light C for identification information is subjected to phase modulation by the modulation circuit section 53, only the interference component of the reflected light D for reference and the reflected light C for identification information is detected, and the background light is not detected. Therefore, the noise components can be canceled out to improve the detection sensitivity.

At this time, the movable mirror 53a is moved by the length of the identification information reflecting portion 15 to change the optical path length difference, so that the reference reflected light D and the identification information for every several hundred μm are formed. An interference waveform with the reflected light C can be sequentially obtained.

FIG. 7 shows a specific example of the optical component for identifying the optical line (however, only the reflective component is shown). The optical fiber 72 is fixed to the optical fiber 72 by the ferrule 71.
The slit 74 with a width of 15 μm that cuts to the core 73 of
It is provided at intervals of 200 μm corresponding to the identification information “1101”.

FIG. 8 shows a waveform when the above-mentioned optical component is actually measured by the measuring method of the above-mentioned embodiment.
In the figure, the horizontal axis represents the optical path length difference, the vertical axis represents the reflectance, and the diagonal axis represents the distance from the measurement position to the installation position of the optical component. Here, the distances of 0, 2, 4, 8, 10, 12, 16 km are shown. The measured waveform at the time is shown.

Thus, according to this embodiment, 16 km
It can be seen that the previously installed optical component for optical line identification can be measured without the need for the reference optical fiber.

[0034]

As described above, according to the first aspect of the invention, the identification information reflecting portion can generate the identification information reflected light, and the reference reflecting portion can generate the reference reflected light. It is possible to extract the change of the light intensity representing the identification information by interfering these,
It is possible to implement a measurement method that does not require a reference optical fiber, and it is possible to obtain the reflected light for identification information and the reflected light for reference from the same optical line, and to measure the distance from the measurement position to the installation position of the optical component. Since the deterioration of the measurement resolution due to the extension can be reduced, it is not necessary to widen the arrangement interval of each reflection point in the optical component, and it is possible to provide the optical component for optical line identification of a very small size.

According to the second aspect of the present invention, the reflection point can be formed only by cutting the optical fiber, and the optical component for optical line identification which is easy to manufacture and inexpensive can be provided.

According to the third aspect of the invention, the reflected light including the reflected light for identification information and the reflected light for reference is provided by injecting low coherence light into the optical component for optical line identification through the optical line. Then, this is divided into two, and one reflected light is delayed with respect to the other reflected light to be combined to cause interference, and by changing the delay amount, reflection for identification information of the optical component for optical line identification is performed. Since the interference light corresponding to each reflection point in the section can be obtained, the identification information can be taken out without the need for the reference optical fiber, and
Since the reflected light for identification information and the reflected light for reference can be obtained from the same optical line, the deterioration of the measurement resolution due to the extension of the distance from the measurement position to the installation position of the optical component can be reduced,
It is not necessary to widen the arrangement interval of each reflection point in the optical component, and it is possible to provide an optical component for optical line identification that is microminiature.

Further, according to the invention of claim 4, the reflected light including the reflected light for identification information and the reflected light for reference is incident on the Mach-Zehnder interferometer, and is bisected by the first optical coupler, and one reflected light is The light delayed by the optical delay circuit section, the other reflected light is phase-modulated by the modulation circuit section, and the second reflected light is combined and interfered by the second optical coupler to output the light output from the second optical coupler. By detecting the intensity with a detector and changing the delay amount in the optical delay circuit section, it is possible to obtain interference light corresponding to each reflection point in the identification information reflection section of the optical component for optical line identification. The identification information can be taken out without the need for an optical fiber, and since the reflected light for identification information is subjected to phase modulation by the modulation circuit unit, only the interference component with the reflected light for reference is detected and the background light Because it is not detected, whereby it is possible to improve the detection sensitivity.

According to the fifth aspect of the invention, the two output lights output from the second optical coupler, that is, the interference lights are converted into electric signals by the two photodetectors, and added by the differential amplifier. However, after that, since the signal amplitude of the modulation frequency in the Mach-Zehnder interferometer or its harmonic component is detected by the vector signal analyzer, it is possible to cancel the noise signals to each other, thereby improving the detection sensitivity.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an optical component for optical line identification of the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional telemetry method.

FIG. 3 is a configuration diagram showing details of a reflective component in FIG.

FIG. 4 is a diagram showing the measurement principle of the telemetry method of the present invention.

FIG. 5 is a block diagram showing an embodiment of an apparatus for carrying out the telemetry method of the present invention.

6 is a configuration diagram showing details of a Mach-Zehnder interferometer and a detector in FIG.

FIG. 7 is a diagram showing a specific example of an optical component for identifying an optical line.

FIG. 8 is a diagram showing a result of measuring the optical component of FIG. 7 by a remote measuring method of the present invention.

[Explanation of symbols]

10 ... Optical component for optical line identification, 11 ... Wavelength selection component, 12
... Reflecting component, 13 ... Optical fiber, 14 ... Core, 15 ... Identification information reflecting section, 16 ... Reference reflecting section, 17 ... Slit, 20 ... Light source, 30 ... Reflected light separating section, 40 ... Optical line,
50 ... Mach-Zehnder interferometer, 51, 52 ... Optical coupler,
53 ... Optical delay circuit section, 54 ... Modulation circuit section, 60 ... Detector, 61, 62 ... Photodetector, 63 ... Differential amplifier, 64 ... Vector signal analyzer.

Claims (5)

[Claims] 1. An optical component for identifying an optical line, which is provided at a predetermined position of an optical line and is provided with identification information for identifying the optical line, identification information depending on whether or not reflection points are provided at predetermined intervals. And a reference reflection portion including a reflection point provided at a distance longer than the entire length of the identification information reflection portion between the identification information reflection portion and the identification information reflection portion. A characteristic optical component for optical line identification. 2. The reflection point is constituted by a slit reaching the core of the optical fiber.
The optical component for optical line identification described. 3. A distance longer than the total length of the identification information reflection section between the identification information reflection section, which represents identification information depending on whether or not reflection points are provided at predetermined intervals, and the identification information reflection section. A low-coherence light is incident on an optical line provided at a predetermined position with an optical component for identifying an optical line having a reference reflection part formed of a reflection point provided apart from the optical component for identifying the optical line. The reflected light is divided into two, the reflected light of one of the two is delayed, the reflected light of the other is modulated, and the reflected light is recombined, and the delay amount is divided into the reflecting portion for identification information and the reflecting portion for reference. A remote measuring method of an optical component for optical line identification, which is characterized in that a change in the light intensity of the combined light is measured while changing an amount corresponding to a distance between them as a center. 4. A light source that generates low-coherence light, an identification information reflector that represents identification information for the light from the light source at each predetermined interval, and an identification information reflector. And an optical line identification optical component provided with a reference reflection section composed of reflection points provided at a distance longer than the entire length of the identification information reflection section in an optical line provided at a predetermined position. A reflected light splitting unit that splits and outputs the light that is incident and that is emitted from the optical line, a first optical coupler that splits the light output from the reflected light splitting unit, and one of the two split light beams. A Mach-Zehnder interferometer including an optical delay circuit section for giving a delay, a modulation circuit section for phase-modulating the other half of the light, and a second optical coupler for recombining the respective lights, and a second light And a detector for detecting the light intensity of the output light from the coupler, While changing the delay amount with an amount corresponding to the distance between the identification information reflection unit and the reference reflection unit as a center,
Telemetry device for optical components for optical line identification, characterized by measuring the change in the light intensity of the output light from the optical coupler. 5. Two photodetectors for respectively converting the two output lights output from the second optical coupler into electric signals,
A differential amplifier that adds the output signals of the two photodetectors;
5. The optical line identifying light according to claim 4, wherein a detector comprising a vector signal analyzer for detecting the signal amplitude of the modulation frequency or its harmonic component in the Mach-Zehnder interferometer from the output signal of the differential amplifier is used. Telemetry device for parts.