JP2010199856A - Optical facility identification method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical facility identification method for an integrated optical fiber communication network that identifies types and positions of optical facilities in service and in real-time, without using a database. <P>SOLUTION: The optical facility identification method is configured; in a such a way that a test light is made incident from one end of an optical path 17 so as to measure the intensity change of a polarization component, distributed in the longitudinal direction of the optical path 17, from a change over time of a polarization component of back-scattered light by the test light, and optical facility, including the bending diameter of the optical fiber corresponding to the period of the intensity change of the polarization component, is identified. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical equipment identification method and apparatus that can identify the type and position of optical equipment constituting an optical fiber communication network from the inside in maintenance and operation of the optical fiber communication network.

  In the maintenance and operation of the optical fiber communication network, accurate and fresh information management of the optical equipment constituting the communication network is desired. In particular, when an optical line breaks down, an optical equipment identification method that identifies the failed optical equipment is important. A conventional optical equipment identification method (for example, see Patent Document 1) will be described. First, the distance loss measurement of the target optical line is performed using an OTDR (Optical Time Domain Reflectometry) method, which is a standard optical evaluation method for optical fiber communication networks.

  FIG. 6 is an explanatory diagram showing the structure of a conventional OTDR method. In FIG. 6, 1 is a test light transmitter, 2 is a test light detector, 4 is an optical coupler, 9 is a PC control unit, 10 is an OTDR test device, 11 is an in-house device (OLT), 12 is an optical coupler, and 13 is an optical coupler. An optical cable, 14 is an optical fiber housing section, 15 is a home wiring, 16 is a terminating device (ONU), 17 is an optical line, 18 is an in-house optical wiring, and 19 is a filter.

  As shown in FIG. 6, the OLT 11 and the ONU 16 for communication are connected and communicated with the in-house optical wiring 18 and the optical line 17 by the optical coupler 12 that inputs / outputs test light to / from the optical line 17.

The OTDR test apparatus 10 is connected to the in-house optical wiring 18 and the optical line 17 using the optical coupler 12.
The OTDR test apparatus 10 includes a test light transmitter 1, a test light detector 2, an optical coupler 4, and a PC control unit 9.

  The test light transmitter 1 uses a 1.65 μm wavelength laser as test light. By using the maintenance wavelength (U-band) and installing a filter 19 that blocks the test light in front of the communication light detector of the ONU 16, only the communication light is transmitted to the ONU 16. Therefore, an in-service optical test can be performed for communication light of 1.26 μm to 1.625 μm.

  The test light transmitted from the test light transmitter 1 propagates through the optical couplers 4 and 12 while being backscattered through the optical line 17. The backscattered light of the optical line 17 passes through the optical couplers 12 and 4, is detected by the test light detector 2, and is photoelectrically converted. The detection signal detected by the test light detector 2 is plotted as a backscattered light intensity with respect to the distance in the longitudinal direction of the optical line 17 by the PC control unit 9 to be a graph. The above is the OTDR method.

  FIG. 5 is an explanatory diagram showing evaluation results of optical lines having connectors and fusion points by the conventional OTDR method. As shown in FIG. 5, the reflection 52 and the loss 53 are caused by a connector and a fusion point existing in the optical line 17, respectively. In order to manage the optical equipment, the equipment database 54 is constructed in advance.

  For example, when a loss occurs in the reflection 52 and a failure occurs in communication, the facility database 54 is used for repair, and the position of the connector or fusion point is compared with the failure occurrence position by the OTDR method. . Here, when the reflection 52 is observed at the 10 km point, the optical equipment at the same location in the database 54 is confirmed. If it is recorded as a connector in the equipment database 54, this reflection 52 is due to the connector connection, and a manhole number or the like is specified as equipment in which the connector is accommodated, so that optical equipment can be identified.

  Similarly, for the loss 53, the optical equipment on the optical line 17 can be identified from the OTDR measurement result. As a result, when the optical line 17 breaks down, it is possible to determine which optical equipment should be repaired or the like.

Japanese Patent Publication No. 7-28266

Amnon Yalib Kunio Tada, Takeshi Kamiya (Director) “Basics of Optoelectronics” Maruzen Publishing 2002 p. 16-31. Takao Matsumoto, Ryo Nagase and Haruo Kano "Proposal of Infinitely Rotating Wavelength Element and its Application to Lightwave Technology" IEICE Transactions Vol. J70-C No. 7 1987 pp. 1021-1030. Ichiro Nakahara “Materials Mechanics (Vol.1)” Published by Yokendo May 1, 1965 p. 228-233. Yoshikazu Namekawa et al. "Development of optical curl cord using holey fiber" The Institute of Electronics, Information and Communication Engineers B-10-4 2004 p. 375.

  However, in order to identify the optical equipment by the conventional OTDR method, the information on the connection point is important. However, an error occurs in the measurement result due to the difference between the length of the optical fiber cable and the actual length, and the low-loss fusion is required. At the arrival point, it may be difficult to detect the cable connection point. In addition, there is a problem that an OTDR measurement result and a database collation error occur due to database update or data input error due to human error. As a result, there is a problem that failure equipment cannot be specified and repair time is long.

  Furthermore, conventionally, in order to identify optical equipment, it is necessary to construct a database in advance, and it is difficult to grasp the optical line state in real time. In addition, when the equipment position is changed in the maintenance work of the optical equipment, database update work occurs, and the work volume increases.

  The present invention has been made in view of the above circumstances, and provides an optical equipment identification method and apparatus for a comprehensive optical fiber communication network that identifies the type and position of optical equipment in real time without using a database. For the purpose.

  In order to solve the above-described problems, the optical equipment identification method of the present invention is a method in which pulsed light is incident from one end of an optical line, and is distributed in the longitudinal direction of the optical line from time variation of the polarization component of backscattered light by the pulsed light. And measuring an intensity change of the polarization component to be identified, and identifying an optical equipment having a bending diameter of the optical fiber corresponding to a period of the intensity change of the polarization component.

  Also, the optical equipment identification method of the present invention measures the intensity change of the polarization component distributed in the longitudinal direction of the optical line from the time change of the polarization component of the backscattered light by the pulse light incident from one end of the optical line. An optical equipment having an optical fiber bending diameter corresponding to a frequency at which the intensity of the polarization component intensity change becomes a peak by converting the intensity change of the polarization component into a polarization component intensity change with respect to the frequency by frequency analysis for each fixed section. Is identified in the longitudinal direction of the optical line.

  In the optical equipment identification method, the present invention is characterized in that the diameter of the coiled optical fiber is used as the bending diameter of the optical fiber.

  In the optical equipment identification method of the present invention, the test light is incident from one end of the optical line, and the intensity change of the polarization component distributed in the longitudinal direction of the optical line is measured from the time change of the polarization component of the backscattered light by the test light. The optical cable having a diameter corresponding to the period of the intensity change of the polarization component is identified.

  In the optical equipment identification method of the present invention, the test light is incident from one end of the optical line, and the intensity change of the polarization component distributed in the longitudinal direction of the optical line is measured from the time change of the polarization component of the backscattered light by the test light. Then, the extension given to the curl cord is determined from the period of the intensity change of the polarization component.

  Further, the optical equipment identification device of the present invention is selected by the test light transmitter for entering the test light from one end of the optical line, the polarizer for selecting the polarization component of the backscattered light by the test light, and the polarizer. A test light detector that detects a time change in the polarization component of the backscattered light and converts it into an electrical signal, and samples the electrical signal converted by the test light detector to calculate the distance from the time, and the longitudinal direction of the optical line An A / D conversion unit that obtains a change in polarization component intensity distributed in the unit, and means for identifying an optical facility having a bending diameter of an optical fiber corresponding to the period of the polarization component intensity change obtained by the A / D conversion unit It is characterized by comprising.

  Further, the optical equipment identification device of the present invention is selected by the test light transmitter for entering the test light from one end of the optical line, the polarizer for selecting the polarization component of the backscattered light by the test light, and the polarizer. A test light detector that detects a time change in the polarization component of the backscattered light and converts it into an electrical signal, and samples the electrical signal converted by the test light detector to calculate the distance from the time, and the longitudinal direction of the optical line An A / D conversion unit that obtains a change in polarization component intensity distributed in the FFT, and an FFT (Fast) that converts the polarization component intensity change obtained by the A / D conversion unit into a change in polarization component intensity with respect to frequency by frequency analysis for each fixed interval. A Fourier Transform (Fourier Transformation) unit and an optical fiber having a bending diameter of the optical fiber corresponding to the frequency at which the intensity of the polarization component intensity change obtained by the FFT unit peaks. An equipment identification unit for identifying the equipment in the longitudinal direction of the optical line; and an evaluation result display unit for displaying the optical equipment identified by the equipment identification unit in the longitudinal direction of the optical line. is there.

  According to the present invention, in the optical equipment identifying apparatus, the diameter of the coiled optical fiber is used as the bending diameter of the optical fiber.

  Further, the optical equipment identification device of the present invention is selected by the test light transmitter for entering the test light from one end of the optical line, the polarizer for selecting the polarization component of the backscattered light by the test light, and the polarizer. A test light detector that detects a time change in the polarization component of the backscattered light and converts it into an electrical signal, and samples the electrical signal converted by the test light detector to calculate the distance from the time, and the longitudinal direction of the optical line And an A / D converter that obtains a change in the polarization component intensity distributed to the optical fiber, and means for identifying an optical cable having a diameter corresponding to the period of the change in the polarization component intensity obtained by the A / D converter. To do.

  The optical equipment identification method and apparatus of the present invention makes it possible to identify optical equipment in real time without a database by observing the period of polarization intensity change from the polarization component of the OTDR waveform and performing an in-service test to identify the optical equipment. It is possible to identify optical equipment of a comprehensive optical fiber communication network such as an optical closure, an optical cable, and a home wiring.

It is a flowchart which shows the optical equipment identification method which concerns on embodiment of this invention. It is composition explanatory drawing which shows an example of the optical equipment identification device which concerns on embodiment of this invention. It is explanatory drawing which shows the evaluation method of the optical equipment identification which concerns on embodiment of this invention. It is explanatory drawing which shows the cable classification identification method of the continuous cable which concerns on embodiment of this invention. It is explanatory drawing which shows the conventional optical equipment identification method. It is structure explanatory drawing for demonstrating the conventional OTDR method. It is a perspective view which shows the optical fiber cross section used by embodiment of this invention. It is explanatory drawing which shows the diameter of the optical equipment used by embodiment of this invention. It is structure explanatory drawing which shows the other example of the optical equipment identification device which concerns on embodiment of this invention. It is composition explanatory drawing which shows expansion | extension of the curl cord which concerns on embodiment of this invention. It is a characteristic view showing the relationship between the extension of the curl cord used in the embodiment of the present invention and the change in the polarization intensity period.

Hereinafter, embodiments of the present invention will be described in detail.
[Embodiment 1]
FIG. 2 shows an example of the optical equipment identification device of the present invention. In FIG. 2, the same parts as those in FIG. In FIG. 2, 3 is a polarizer, 5 is an A / D conversion unit, 6 is an FFT (Fast Fourier Transform) unit, 7 is an equipment identification unit, 8 is an evaluation result display unit, and 100 is an optical equipment identification device. The polarizer 3 is provided between the test light detector 2 and the optical coupler 4, and the A / D conversion unit 5, the FFT unit 6, the equipment identification unit 7, and the evaluation result display unit 8 are included in the PC control unit 9. Provided.

  As shown in FIG. 2, the test light (pulse light) is incident on one end of the optical line 17 from the test light transmitter 1 via the optical couplers 4 and 12. The backscattered light from the test light returning from the optical line 17 is subjected to polarization component selection into s wave or p wave by the polarizer 3 through the optical couplers 12 and 4. The test light detector 2 detects the time change of the s wave or p wave, which is the polarization component of the backscattered light selected by the polarizer 3, and converts it into an electrical signal. Thereafter, sampling is performed by the A / D conversion unit 5 to calculate the distance from the measurement time, and the back scattered light is a change in the intensity of the s wave or p wave that is the polarization component of the back scattered light distributed in the longitudinal direction of the optical line 17. Get the intensity graph.

  FIGS. 3A to 3C show the optical equipment identification evaluation method of the present invention. When the backscattered light intensity graph is changed to an s wave or p wave that is a polarization component of the backscattered light, and the optical fiber is in a coiled bent accommodation state (bending diameter) in the optical equipment, a birefringence difference occurs, A polarization component intensity change period occurs in the OTDR waveform as shown in FIG. By comparing this polarization component intensity change period and the bending diameter of the optical fiber in the optical equipment, an optical equipment having an optical fiber bending diameter corresponding to a predetermined polarization component intensity change period can be identified.

  Here, the principle of a method for obtaining the bending diameter of the optical fiber from the polarization intensity change period will be described. The aforementioned backscattered light includes a vertical component (s wave) and a horizontal component (p wave) as seen from the cross section of the optical fiber shown in FIG. 7, and the polarization intensities Is and Ip of these s wave and p wave are: It can be expressed as shown in the Jones matrix (for example, see Non-Patent Document 1).

（但し、Ｉ_０：後方散乱光強度［ｍＷ］、θ：入力角、ε：位相進みである。）

(However, I ₀ : Backscattered light intensity [mW], θ: input angle, ε: phase advance.)

Here, the phase advance ε is ε = 2β · l (2)
(Where, β: birefringence difference, l: optical fiber length [m])
It expresses. Where β is
β = C _f (d / D) ² (3)
D: Diameter of coiled optical fiber [m], d: Clad diameter of optical fiber [m], _Cf optical fiber characteristic constant (constant determined by material, refractive index, wavelength, etc.) are known (for example, Non-patent document 2).

When the twisting element of the optical fiber is considered, the polarized light rotates in the positive (or negative) direction with respect to the input angle θ, and a twist of 2π is added every time the circumference of the coiled optical fiber is made. Therefore, every time Δl advances, the input angle of Δθ changes. In the formula:
(Δθ / Δl) = (2π / Dπ) = 2 / D (4.1)
The input angle θ ′ with respect to the distance is given by the following equation.
θ ′ = θ ± (2 l / D) (4.2)

In consideration of the above, the polarization intensities Is and Ip are as follows.

In the above formula, the (θ ± (2l / D)) portion is related to the amplitude, and the (C _f (d / D) ² · l) portion is related to the period. If l is obtained when the period is π, the period L can be calculated by assuming that l for one period with respect to the diameter of the coiled optical fiber is L.
L = (π / C _f ) · (D / d) ² (10)
(However, L: Period [m])

Here, 439 [rad / mm] is used as C _f from Non-Patent Document 2 described above. As shown in FIG. 3A, when polarization intensity change periods of 40 cm, 160 cm, and 10 cm are seen on the OTDR waveform, the optical fiber states are D = 3 cm, 6 cm, and 1.5 cm, respectively. I understand that. In the optical line equipment, since the optical fiber has the diameter shown in FIG. 8, if these periods appear in the OTDR waveform, the SZ cable, the optical closure, the curl cord, and the optical equipment can be distinguished from each other.

FIG. 1 is a flowchart showing an optical equipment identification method according to the present invention.
[1] Test light is incident on one end of the optical line 17 to be measured, and the backscattered light, which is return light from the test light, is selected by the polarizer 3 into s waves (p waves), and the backscattered light is selected. The scattered light intensity graph is created by measuring the intensity change of the polarization component distributed in the longitudinal direction of the optical line from the time change of the polarization component of the light.

  [2] Next, in step S1, the period of the intensity change of the polarization component generated in the scattered light intensity graph is detected for each Δx section.

  [3] Next, in step S2, the intensity change period detected in [2] was determined by comparing the accommodation bending state (bend diameter) of the optical fiber existing in the optical equipment with the calculated intensity change period by the bend diameter. An optical equipment including an optical fiber having a bending diameter is specified.

  [4] Next, if the measurement point remains in step S3, the process returns to [2]. If the measurement point does not remain, the distribution of the optical equipment is analyzed in the longitudinal direction in step S4, and the process ends.

  By using the above optical equipment identification method, equipment location information can be obtained in real time even if the optical equipment is changed. Further, when there is already a database, the facility position information and the database information can be matched to correct an error in the database. Furthermore, a route map can be created by grasping the optical path through which the test light passes from the optical equipment and matching it with the map information.

[Embodiment 2]
In the first embodiment, when the period is read from the OTDR waveform, in order to detect clearly, the OTDR waveform is divided in the longitudinal direction for each Δx, and FFT analysis is performed.

Δx corresponds to the distance resolution in the longitudinal direction regarding the identification of the optical equipment, and FFT analysis can be performed if a quarter period or more of the polarization intensity change period is known. Therefore, the minimum distance resolution Δx _max is defined as D _{max being} the diameter of the largest optical fiber in the optical equipment in the optical line 17.
Δx _max = (1/4) · (π / C _f ) · (D _max / d) ² (11)
It becomes.

  As an OTDR waveform, a digital signal obtained by analog-digital conversion of the time-varying signal output from the test light detector 2 by the A / D converter 5 is FFT-analyzed by the FFT unit 6 and converted into a polarization intensity graph with respect to frequency. To do.

  Here, the frequency at which the polarization intensity reaches a peak is obtained, and the equipment identifying unit 7 identifies the optical equipment that matches the frequency defined in advance. The determination result is displayed on the evaluation result display unit 8.

  As shown in the first embodiment, the frequency corresponding to the FFT period of the change in polarization intensity at each analysis point shown in FIG. 3B is 40 cm, 160 cm, and the frequency of the SZ cable, optical closure, and curl cord is 40 cm, 160 cm, Since it is 10 cm, the frequencies are 500 MHz, 130 MHz, and 2000 MHz, respectively. In the interval where the frequency is 130 MHz and the frequency is 130 MHz, the optical equipment can be identified as having the optical closure (D = 6 cm). Similarly, 500 MHz can be identified as an SZ cable (D = 3 cm), and 2000 MHz can be identified as a curled cord (D = 1.5 cm). When Δx includes two or more facilities, each peak is detected. For example, when the optical closure and the SZ cable are included in the Δx section, peaks at 130 MHz and 500 MHz are detected. In this way, by determining the optical equipment for each Δx in the longitudinal direction using FFT, it becomes possible to quantify the fluctuation of the periodic change described in the first embodiment, and more clearly, FIG. As described above, the optical line 17 can identify the equipment state of the SZ cable, the optical closure, and the curl cord.

  As described above, according to the optical equipment identification device of the second embodiment, the test light transmitter 1 enters the test light from one end of the optical line 17, and the polarizer 3 selects the polarization component of the backscattered light by the test light. To do. The test light detector 2 detects the time change of the polarization component of the backscattered light selected by the polarizer 3 and converts it into an electric signal. The A / D converter 5 is converted by the test light detector 2. The electric signal is sampled, the distance is calculated from the time, and the change in the polarization component intensity distributed in the longitudinal direction of the optical line 17 is obtained. The FFT unit 6 converts the polarization component intensity change obtained by the A / D conversion unit 5 into a polarization component intensity change with respect to the frequency by frequency analysis for each fixed section, and the equipment identification unit 7 is obtained by the FFT unit 6. The optical equipment having the bending diameter of the optical fiber corresponding to the frequency at which the intensity of the polarization component intensity change reaches the peak is identified in the longitudinal direction of the optical line 17, and the evaluation result display unit 8 is identified by the equipment identification unit 7. The optical equipment is displayed in the longitudinal direction of the optical line 17.

[Embodiment 3]
FIG. 4 shows a cable type identification method for continuous cables.
As shown in FIG. 4A, in an optical line, a multi-core optical cable is usually used at the in-house termination, and a small-core optical cable is connected and used as the wiring extends to the user's house. If the optical cable is multi-core, the cable diameter is large. For example, the optical lines composed of 1000-core cable and 100-core cable have different diameters, such as D = 4 cm and 1.5 cm, respectively. When the diameter is reduced, the birefringence difference β shown in the equation (3) is increased and the polarization intensity change period is shortened. In the case of a single core cable, there is almost no diameter, and the polarization intensity change period is not seen.

  That is, as shown in FIG. 4A, when optical cables having different diameters are connected as the optical line 17 using the first embodiment, the result of measuring the polarization intensity in the longitudinal direction is as shown in FIG. As shown in FIG. 4, when the polarization intensity change period corresponding to each cable diameter is shown and the period is 75 cm, 10 cm, and 0 cm, respectively, a 1000-core cable, a 100-core cable, and a single-core cable are obtained.

  As described above, the type of cable can be specified by detecting the period of polarization intensity change for each optical cable. Further, by specifying the boundary point of the polarization intensity change period, it is possible to optically determine the branch point of the cable, which has been difficult to specify so far, from the inside.

[Embodiment 4]
Next, a method for identifying the extension of the curl code will be described. As shown in FIG. 10, when a tension is applied to the curl cord in the longitudinal direction, a shear stress is applied to the inside of the coiled optical fiber. The shear stress compresses the cross section of the optical fiber positioned perpendicular to the direction in which the curl cord is pulled, enlarges the birefringence difference in the x and y directions due to the strain shown in FIG. 7, and shortens the polarization intensity change period. The tension P and shear stress τ at this time are

P = kδ (12)
τ = (8 · PD / πd ³ ) × (1 + d / 2D) (13)
(Where k: spring constant [N / m], δ: elongation [m])
(For example, see Non-Patent Document 3). When the winding number is 90, the spring constant k is 3.47 × 10 ⁻³ ) [N / mm]) (for example, see Non-Patent Document 4).

  An increase in correction birefringence difference can represent a change in diameter D in a pseudo manner. The diameter D ′ (D> D ′) of the reduced coiled optical fiber is a value obtained by adding the shear stress τ,

D ′ = D−C _t τ (14)
It is defined as For example, as shown in FIG. 11, the constant C _t is 1.04 as a value obtained by plotting experimental values on a graph in which the horizontal axis is expansion δ and the vertical axis is the polarization intensity change period, and is obtained from the slope of the waveform. ^{× 10 -4 [mm 3 / N} ] is obtained.

By using the equations (10) and (12) to (14), the extension of the curl cord can be calculated from the polarization intensity change period.
For example, when the polarization intensity change is measured using the curled optical fiber cord having a predetermined period for the home wiring using the first embodiment, and the polarization intensity change period is 3.8 cm, the curl cord It can be seen that the extension is 80 cm.

  From the above, by detecting the period of change in the polarization intensity of the home wiring, it is possible to know the extension status of the curl cord in the wall, which is difficult for humans to enter, and the magnitude of the load on the curl cord in the longitudinal direction. Can be judged.

[Embodiment 5]
FIG. 9 shows another example of the optical equipment identification device of the present invention, and a method for measuring the optical equipment in the optical line 17 in real time using only the optical equipment identification method of Embodiment 1 will be described. .

  An optical equipment identification device 100 and an optical coupler 12 that guides the test light to the optical line 17 for identifying the equipment are installed in advance in the facility that accommodates the optical fiber. The measurer 82 operates the optical equipment identification device 100 using the operation terminal 81, measures the distance-polarization intensity of the optical line 17 in real time, and performs distance-optical equipment measurement. From the measurement result, it is possible to grasp the installation status of the reliable optical equipment.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Test light transmitter, 2 ... Test light detector, 3 ... Polarizer, 4 ... Optical coupler, 5 ... A / D conversion part, 6 ... FFT part, 7 ... Equipment identification part, 8 ... Evaluation result display part, DESCRIPTION OF SYMBOLS 9 ... PC control part, 10 ... OTDR test apparatus, 11 ... In-house apparatus (OLT), 12 ... Optical coupler, 13 ... Optical cable, 14 ... Optical fiber accommodating part, 15 ... In-home wiring, 16 ... Termination apparatus (ONU), 17 DESCRIPTION OF SYMBOLS ... Optical line, 18 ... In-house optical wiring, 19 ... Filter, 100 ... Optical equipment identification device.

Claims (9)

  The test light is incident from one end of the optical line, the intensity change of the polarization component distributed in the longitudinal direction of the optical line is measured from the time change of the polarization component of the backscattered light by the test light, and the intensity change period of the polarization component An optical equipment identification method characterized by identifying an optical equipment having a bending diameter of an optical fiber corresponding to.   The test light is incident from one end of the optical line, the intensity change of the polarization component distributed in the longitudinal direction of the optical line is measured from the time change of the polarization component of the backscattered light by the test light, and the intensity change of the polarization component is constant. An optical equipment having a bending diameter of the optical fiber corresponding to the frequency at which the intensity of the change in polarization component intensity reaches a peak is identified in the longitudinal direction of the optical line by converting the change in polarization component intensity with respect to the frequency by frequency analysis for each section. The optical equipment identification method characterized by the above-mentioned.   The optical equipment identification method according to claim 1 or 2, wherein the diameter of the coiled optical fiber is used as the bending diameter of the optical fiber.   The test light is incident from one end of the optical line, the intensity change of the polarization component distributed in the longitudinal direction of the optical line is measured from the time change of the polarization component of the backscattered light by the test light, and the intensity change period of the polarization component An optical equipment identifying method characterized by identifying an optical cable having a diameter corresponding to   The test light is incident from one end of the optical line, the intensity change of the polarization component distributed in the longitudinal direction of the optical line is measured from the time change of the polarization component of the backscattered light by the test light, and the intensity change period of the polarization component And determining an extension given to the coiled optical fiber. A test light transmitter for injecting test light from one end of the optical line;
A polarizer for selecting a polarization component of backscattered light by the test light;
A test light detector for detecting a time change of a polarization component of backscattered light selected by the polarizer and converting it into an electrical signal;
An A / D converter that samples the electrical signal converted by the test photodetector and calculates a distance from the time to obtain a polarization component intensity change distributed in the longitudinal direction of the optical line;
An optical equipment identification device comprising: an optical equipment having an optical fiber bending diameter corresponding to a period of change in polarization component intensity obtained by the A / D converter. A test light transmitter for injecting test light from one end of the optical line;
A polarizer for selecting a polarization component of backscattered light by the test light;
A test light detector for detecting a time change of a polarization component of backscattered light selected by the polarizer and converting it into an electrical signal;
An A / D converter that samples the electrical signal converted by the test photodetector and calculates a distance from the time to obtain a polarization component intensity change distributed in the longitudinal direction of the optical line;
An FFT unit that converts the polarization component intensity change obtained by the A / D conversion unit into a polarization component intensity change with respect to frequency by frequency analysis for each fixed section;
An equipment identification unit for identifying an optical equipment having a bending diameter of an optical fiber corresponding to a frequency at which the intensity of the polarization component intensity change obtained in the FFT unit becomes a peak, in the longitudinal direction of the optical line;
An optical equipment identification apparatus, comprising: an evaluation result display section that displays the optical equipment identified by the equipment identification section in the longitudinal direction of the optical line.   The optical equipment identification device according to claim 6 or 7, wherein the diameter of the coiled optical fiber is used as the bending diameter of the optical fiber. A test light transmitter for injecting test light from one end of the optical line;
A polarizer for selecting a polarization component of backscattered light by the test light;
A test light detector for detecting a time change of a polarization component of backscattered light selected by the polarizer and converting it into an electrical signal;
An A / D converter that samples the electrical signal converted by the test photodetector and calculates a distance from the time to obtain a polarization component intensity change distributed in the longitudinal direction of the optical line;
An optical equipment identification device comprising: means for identifying an optical cable having a diameter corresponding to a period of a change in polarization component intensity obtained by the A / D conversion unit.

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