JP5117037B2 - Optical fiber discrimination device and discrimination method - Google Patents

Description

  The present invention relates to an optical core discriminating device and an optical core discriminating method used to perform optical fiber line contrast, live line determination, and the like.

  As a communication system using an optical fiber, PDS (Passive Double Star) communication or PON (Passive Optical Network) communication as shown in FIG. 5 is known. In the PDS (PON) communication system 900, a downstream optical signal λ91 from an OLT (Optical Line Terminal) 901 is branched by a splitter 902 and transmitted to a plurality of user side ONUs (Optical Network Units) 903. Each ONU 903 (ONU1 to ONU4) selects and acquires only the optical signal addressed to itself. The downstream optical signal λ91 includes a signal for controlling the transmission timing of the upstream optical signal λ92 transmitted from each ONU 903.

  Each optical signal λ 92 sent from each ONU 903 is input to the OLT 901 by a signal string T that is combined by a splitter 902 and at a timing specified by the OLT 901. In the OLT 901, the signal sequence T of the upstream optical signal λ 92 is divided into optical signals for each ONU 903.

  In the PDS (PON) communication system 900 having the above-described configuration, for example, when there is an application for abolition of one ONU 903 (referred to as ONU 1) and the line from the splitter 902 to the ONU 1 is to be removed, the exit from the splitter 902 is usually used. It is determined which port of the splitter 901 is connected to the ONU 1 at the T point on the side.

  As a method for discriminating unused ones from a plurality of core wires housed in an optical fiber cable, a special optical signal (for example, an optical signal modulated to a frequency of 270 Hz) is usually used from one end of the core wire. Is detected, and the detection circuit detects the light received and detected using a light receiving element on the other end side. As a method for detecting an optical signal using a light receiving element, for example, there is one disclosed in Patent Document 1. Patent Document 1 describes a method in which an optical fiber is partially bent and leakage light emitted to the outside from the bent portion is received and detected by a light receiving element.

  In the PDS (PON) communication system 900, when the optical fiber core discriminating device described in Patent Document 1 is used to detect an unused optical fiber core wire, the power of the ONU 1 scheduled to be discontinued is turned off. Even if λ92 is not transmitted, since the downstream optical signal λ91 from the OLT side is transmitted, the leaked light of this optical signal λ91 is detected and determined to be in the live line state. Therefore, in the PDS (PON) communication system 900, an unused ONU line cannot be specified using the optical fiber identification device described in Patent Document 1.

  Also, a specific optical signal (for example, an optical signal modulated to a frequency of 270 Hz) different from the optical signals λ91 and λ92 is input into the line from the ONU 1 side, and the leaked light is detected at the T point to control the line. It is possible to do. However, it is necessary to prepare an expensive light source device for transmitting modulated light of a specific wavelength on the ONU 1 side, and the modulated light may be input to the OLT to cause an adverse effect, which is not practical.

  Accordingly, a photodetector such as a PD is arranged on the left and right sides of the bent portion of the optical fiber, and a heart for discriminating the light transmission state and the light transmission direction of the optical fiber based on the intensity of the light obtained by the light detector. Line discriminators have been developed. By using this core wire discriminator, for example, when leakage light is detected by the right detector, it can be confirmed that the optical fiber is in a light-transmitting state and is transmitted in the right direction. However, since leakage light is actually detected by the left photodetector, the direction is determined by comparing the magnitudes of the light intensities measured by the left and right photodetectors.

  In recent optical communication systems for final terminals, as described with reference to FIG. 5, communication is performed using optical signals having different wavelengths in the upstream and downstream directions with a single optical fiber. Of these, the optical signal in the downstream direction is branched into a large number by a branching coupler or the like and sent to all downstream optical fibers. Therefore, in order to determine whether or not the fiber core wire is in a live line state, it is necessary to detect and determine whether or not an upstream signal is transmitted.

Japanese Patent Application Laid-Open No. 2005-133867 discloses a core line discriminator that selectively detects a wavelength to be detected with respect to the optical communication as described above in which optical signals having different wavelengths in the upstream and downstream directions are transmitted through one optical fiber. It is disclosed. Patent Document 2 proposes a method in which an optical filter is disposed on the front surface of a photodetector so that light having a wavelength other than the detection target is lost, and only the light to be detected is allowed to pass and measured by the photodetector. . By using an optical filter that passes only the wavelength of the upstream signal to be detected, it is determined whether or not the upstream signal is transmitted.
JP 09-178945 A JP 2004-109401 A

  However, the above conventional techniques have the following problems. In an optical communication system in which different wavelengths of light are transmitted in opposite directions in the same optical fiber, if a conventional core identifier is used to detect whether the fiber core is in a live state, the optical fiber is bent. The left and right detectors in the selected portion add up and measure all the leaked light of each wavelength. For this reason, not only the light intensity for each wavelength cannot be detected, but also the direction in which the light of each wavelength is transmitted from the measured values of the left and right detectors, or the upstream signal is transmitted. I couldn't even judge whether or not.

  For example, in FIG. 5, when a λ91 optical signal is transmitted from the left to the downward direction and a λ92 optical signal is transmitted from the right to the upward direction, leakage occurs at the detectors installed on the left and right of the optical fiber bent portion at the T point. Since light is detected, it is determined that the optical fiber connected to the ONU 1 is in a light-transmitting state. However, since the intensity of each of the optical signals transmitted through the optical fiber is not known, even if the magnitudes of the optical intensities detected by the left and right detectors are compared, the optical signal detected by each detector is a light of λ91. It cannot be determined whether the light is λ92 or not.

  Further, there is a problem that the intensity of leaked light from the bent portion of the optical fiber varies depending on the wavelength. For example, when the wavelength λ91 of the downstream optical signal is 1550 nm and the wavelength λ92 of the upstream optical signal is 1310 nm, the light with a wavelength of 1310 nm has much less leakage light due to bending of the optical fiber than that of 1550 nm. There are features such as. Further, since the 1550 nm light is also received by the detector in the reverse direction, it cannot be determined whether or not the 1310 nm light is transmitted depending on the intensity of the optical signal of each wavelength. Therefore, it is impossible to accurately determine the passage of 1310 nm light by the conventional method.

  In the method using the optical filter described in Patent Document 2, it is necessary to make the optical filter enter the optical filter at a predetermined incident angle in order to cause the optical filter to lose light other than the transmission target wavelength. The leakage direction of light leaking from the light reaches a wide range. Therefore, there is a problem that even if only the light of a specific wavelength is detected by the optical filter, sufficient wavelength selection by the optical filter cannot be realized.

  As an example, an optical filter that can give a loss of 30 dB or more with respect to light of 1550 nm at an incident angle of 0 degree and hardly gives a loss to 1310 nm is used. Only a loss of about 10 dB is given to light. Since the intensity of the optical signal transmitted through the optical fiber is in a wide range of about 0 dBm to −30 dBm, the light detected through the optical filter can be detected, for example, by only giving a loss of about 10 dB. It is impossible to distinguish between leaking light of 1550 nm light passing through at −14 dBm or leaking light of 1310 nm light passing through at an intensity of −24 dBm.

  Therefore, the present invention has been made to solve these problems, and whether or not there is an optical signal having a predetermined wavelength is also applied to an optical transmission line through which optical signals having two or more different wavelengths pass at different intensities. An object of the present invention is to provide an optical core discriminating device and a discriminating method that can be detected with high accuracy.

A first aspect of the optical fiber identification device according to the present invention is an optical fiber identification device that detects the intensity and transmission direction of optical signals having two or more different wavelengths transmitted through an optical fiber. Measuring the leakage light from the optical fiber core wire bent by the bending fixing portion and the bending fixing portion for bending and fixing the optical fiber core wire in order to leak the optical signal from the core wire A detector, and a discrimination processing unit that inputs measurement data from the detector and discriminates the intensity and transmission direction of the optical signal, and the detector has only twice the number of wavelengths of the optical signal. The leakage light is measured by changing measurement conditions, and the discrimination processing unit is configured to determine a ratio of leakage from the optical fiber core wire that is determined in advance depending on a measurement position of the detector and the wavelength (hereinafter referred to as a ratio). Is referred to as input loss). Characterized in that the intensity of the leaked light measured by the vessel is to determine the intensity and the transmission direction of the optical signal.

  Another aspect of the optical fiber identification device of the present invention is characterized in that the measurement condition is determined by the measurement position and the light receiving condition of the detector.

  In another aspect of the optical fiber identification device of the present invention, the measurement condition is that the measurement position is two different points, and the light reception condition of the detector is changed by the number of wavelengths at each measurement position. Features.

  Another aspect of the optical fiber identification device of the present invention is characterized in that the measurement condition changes the measurement position by twice the number of wavelengths.

  In another aspect of the optical fiber identification device of the present invention, the measurement condition and the light receiving condition are set such that a product of the number of the measurement positions and the number of the light receiving conditions is twice the number of wavelengths. It is characterized by changing conditions.

  In another aspect of the optical fiber identification device of the present invention, the light receiving condition is changed by changing the type of the light receiving element of the detector.

  In another aspect of the optical fiber identification device of the present invention, the light reception condition is changed by changing a wavelength selection function provided in the detector.

  In another aspect of the optical fiber identification device of the present invention, the wavelength selection function is an optical filter provided on the front surface of the detector, and the change of the wavelength selection function is performed by changing the wavelength characteristic of the optical filter. It is characterized by being changed.

A first aspect of the optical fiber identification method of the present invention is an optical fiber identification method for detecting the intensity and transmission direction of optical signals having two or more different wavelengths transmitted through an optical fiber, wherein the optical fiber The core wire is partially bent, and the intensity of leaked light from the bent optical fiber core wire is measured by changing measurement conditions by twice the number of wavelengths of the optical signal, and the measurement position of the leaked light and Based on the leakage ratio (hereinafter referred to as input loss) determined in advance depending on the wavelength, the optical signal intensity and transmission direction are determined from the measured leakage light intensity. It is characterized by doing.

  According to the present invention, the light reception measurement value is obtained under different conditions according to the number of wavelengths of the optical signal passing through the optical transmission line, so that the predetermined wavelength passing through the optical transmission line can be obtained. It is possible to provide an optical core discriminating device and a discriminating method capable of discriminating the presence or absence of an optical signal. In particular, for two or more optical signals that pass through the optical transmission line at different wavelengths in the vertical direction, it is possible to detect the intensity and direction of the optical signal for each wavelength with high accuracy.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical fiber identification device and a discrimination method in a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

  For example, in the PON communication system as shown in FIG. 5, the present invention provides an optical core discriminating apparatus and a discriminating method suitable for discriminating whether or not each core wire in an optical fiber cable is connected to an ONU. To do. The optical core line discrimination device according to the first embodiment of the present invention will be described in detail with reference to FIGS. FIG. 2 is a plan view showing a schematic configuration of the optical fiber identification device 100 of the present embodiment. In order to leak an optical signal from the optical fiber core 10 to be detected, the optical fiber core discriminating device 100 bends and fixes the optical signal into a predetermined shape and leaks from the optical fiber core wire 10. There are provided two detectors 121 and 122 for measuring light, and a discrimination processing unit 130 for inputting the measurement data measured by the detectors 121 and 122 and performing processing for discriminating the core.

  The bend fixing part 110 is a guide groove 111 for placing the optical fiber core wire 10, a bend holding part 112 for bending and holding the optical fiber core wire 10 in a predetermined shape, and the optical fiber core wire 10. The movable pressing portion 113 is configured to be pressed and fixed to the holding portion 112. In FIG. 2A, the optical fiber core wire 10 to be measured is placed in the guide groove 111, and the movable pressing portion 113 is moved to the bending holding portion 112 side to fix the optical fiber core wire 10 therebetween. FIG. 2B shows a state where the movable pressing portion 113 is moved to the bending holding portion 112 side and the optical fiber core wire 10 is fixed. Thereby, the optical fiber core wire 10 is bent into a predetermined shape along the bending holding portion 112.

  Since the fiber core wire 10 is bent into a predetermined shape by the bending fixing portion 110, an optical signal transmitted through the core wire 10 easily leaks to the outside. In order to measure this leaked light, detectors 121 and 122 are arranged in the vicinity of the bent core wire 10. Then, the intensity of the leaked light measured by the detectors 121 and 122 is transmitted to the discrimination processing unit 130, and the discrimination processing unit 130 determines the intensity of each optical signal that passes through the fiber core wire 10 in the downstream direction and the upstream direction. It is calculated for each different wavelength.

  In the present embodiment, in order to calculate the intensity of the optical signal transmitted through the core wire 10 based on the intensity of the leaked light input from the detectors 121 and 122 in the discrimination processing unit 130, in this embodiment, the optical signal from the core wire 10. The ratio of leakage (hereinafter referred to as input loss) is obtained in advance through experiments or the like and is calculated using this. The input loss varies depending on the wavelength of the optical signal transmitted through the core wire 10, but also varies depending on the shape of the core wire 10 that is bent and the leakage direction. Therefore, the input loss related to the light leaking in the direction received by the detectors 121 and 122 is determined in advance through experiments or the like.

  A method for calculating the intensity of the optical signal by the discrimination processing unit 130 will be described in detail with reference to FIG. FIG. 1 shows only a part of the optical core discriminating apparatus 100 in detail in order to explain the optical core discriminating method of the present embodiment. Here, for the sake of explanation, the distance between the optical fiber core wire 10 and the detectors 121 and 122 is enlarged and displayed. In the figure, the direction in which the optical fiber core wire 10 transmits light from the left to the right is the down direction, and the opposite direction is the up direction. Here, it is assumed that two types of optical signals of wavelengths λ1 and λ2 (hereinafter referred to as optical signals λ1 and λ2 respectively) pass through the optical fiber 10. For example, optical signals of 1.49 μm and 1.31 μm can be used as the optical signals of wavelengths λ1 and λ2.

  In FIG. 1, the intensities of the optical signal λ1 and the optical signal λ2 that pass in the downstream direction are x and y, respectively, and the intensities that pass in the upstream direction are X and Y, respectively. Further, as input loss that is a ratio leaking in the direction of the detector 121, the downstream optical signals λ1 and λ2 are a and b, respectively, and the upstream optical signals λ1 and λ2 are c and d, respectively. Further, as the input loss with respect to the direction of the detector 122, the downstream optical signals λ1 and λ2 can be set to e and f, and the upstream optical signals λ1 and λ2 can be set to g and h, respectively.

  On the other hand, when the bent shape of the optical fiber 10 and the arrangement of the detectors 121 and 122 and the direction of the light receiving unit are made to be symmetrical with respect to the symmetry axis S shown in FIG. The input loss associated with the device 122 can be replaced with e = c, f = d, g = a, and h = b, respectively. In FIG. 1, as described above, the bending fixing portion 110 is formed so as to be bilaterally symmetric with respect to the symmetry axis S, and the detectors 121 and 122 are disposed. Is replaced with that of the detector 121. By realizing such symmetry, the number of input losses determined in advance can be reduced.

When the input loss is set as described above and the measured values of the leaked light by the detectors 121 and 122 are A and B, respectively, the following relationship is established between the optical signal intensity.
[Equation 1]
ax + by + cX + dY = A (Formula 1)
cx + dy + aX + bY = B (Formula 2)
In the above equation, there are four unknowns x, y, X, and Y, but there are only two equations, so the unknowns x, y, X, and Y cannot be calculated.

Therefore, in the optical fiber identification method of the present embodiment, the measured value when the light receiving conditions of the detectors 121 and 122 are changed is also obtained. When the light receiving condition is changed, the input loss associated with each detector also changes. Therefore, the input loss when the light receiving condition is changed is determined and used in advance. When the input loss a, b, c, d is changed to a ′, b ′, c ′, d ′ by changing the light receiving condition, respectively, the detector 121 when the light receiving condition is changed. , 122, and A ′, B ′, the relationship of the following equation is further established between the intensity of the optical signal.
[Equation 2]
a′x + b′y + c′X + d′ Y = A ′ (Formula 3)
c′x + d′ y + a′X + b′Y = B ′ (Formula 4)

  By using the above (Formula 1) to (Formula 4), the intensities x, y, X, and Y of the optical signal transmitted through the optical fiber core wire 10 can be calculated. As described above, according to the optical fiber identification method of the present embodiment, the measured value when the light receiving conditions of the detectors 121 and 122 are changed is also used, so that the optical signal transmitted through the optical fiber 10 is transmitted. The intensity can be calculated.

  In the present embodiment, two detectors are used, and leakage light is measured under two light receiving conditions for each detector, whereby four equations (equation 1) are obtained for the four unknowns x, y, X, and Y. ) To (Equation 4) are established, whereby the values of the unknowns x, y, X, and Y can be calculated. The number of unknowns is a number obtained by multiplying the number of wavelengths in two directions, the downstream direction and the upstream direction, of the optical fiber core wire 10. In order to satisfy the same number of equations as the number of unknowns, it is possible to change the number of measurement positions by the detector and the light receiving conditions of each measurement device. In the present embodiment, the number of unknowns is four with two wavelengths, and four equations are established by setting the measurement positions of the detectors at two locations and the light receiving conditions of each detector at two types. I am doing so.

  As described above, according to the optical fiber identification method of this embodiment, when the combination of the measurement position of the detector and the light receiving condition of the detector is the measurement condition, the measurement condition is changed according to the number of wavelengths. Thus, the intensity of the optical signal can be calculated. In the discrimination processing unit 130, based on the calculated intensity of each optical signal, whether the optical signal of each wavelength is transmitted in the downstream direction or the upstream direction, or not transmitted at all, etc. Is determined.

  Hereinafter, measurement conditions for the detector will be described in more detail. As described above, the measurement condition is determined by a combination of the measurement position of the detector and the light receiving condition. With this combination, the measurement condition is changed by twice the number of wavelengths of the optical signal, so that the intensity of the optical signal in the downstream and upstream directions is based on the measured values of the detector measured under each measurement condition. Can be calculated. To change the measurement conditions, only the number of measurement positions of the detector may be increased, or only the light reception conditions of the detector may be increased, and the product of the number of measurement positions and the number of light reception conditions is 2 of the number of wavelengths. What is necessary is just to change measurement conditions so that it may be doubled.

  A method of measuring by changing the measurement conditions of the detector will be described using an example shown in FIG. FIG. 3A shows a case where the number of detectors is two as in the above embodiment. In this case, another measurement value can be obtained by changing the light receiving condition of each detector. As a method of changing the light receiving condition, in FIG. 3A, an optical filter 123 is arranged on the light receiving surfaces of the detectors 121 and 122. The optical filter 123 has a transmission gain that differs depending on the wavelength of light to be received. By providing such a wavelength selection function in the detectors 121 and 122, the light receiving condition can be changed.

  FIG. 3B shows an example in which the light receiving condition is changed by changing the type of detector. That is, the light receiving conditions are changed by changing the type of the photodiode (PD) that is the light receiving element of the detectors 121 and 122. As the PD, for example, two types of Ge photodiode and InGaAs photodiode can be used interchangeably. The Ge photodiode and the InGaAs photodiode have different wavelength characteristics of the current conversion value of light intensity, so that it is possible to obtain measured values of light receiving conditions having different wavelength characteristics.

  Further, FIG. 3C shows an example in which the measurement condition is changed by increasing the measurement position of the detector without changing the light receiving condition of the detector. When the number of measurement positions is increased in this way, it is preferable to select a position where the light receiving sensitivity of the detector is good. As a method of increasing the measurement position, the number of detectors may be increased and arranged at each measurement position, or the detector may be moved to each measurement position and measured.

Another embodiment of the optical fiber identification method of the present invention will be described below with reference to FIG. In a normal communication system, the wavelength of each optical signal that passes through the optical fiber in the downstream and upstream directions is often determined in advance, and in this case, the number of unknown optical signals is small. Become. In the example of FIG. 4, it is assumed that the optical signal having the wavelength λ1 is transmitted in the downstream direction and the optical signal having the wavelength λ2 is transmitted in the upstream direction. In this case, the intensity x of the downstream optical signal λ1 and the intensity Y of the upstream optical signal λ2 are unknowns. Therefore, the following expression is established from (Expression 1) and (Expression 2).

[Equation 3]
ax + dY = A (Formula 5)
cx + bY = B (Formula 6)

下り方向の光信号の波長λ１を１．４９μｍとし、上り方向の光信号の波長λ２を１．３１μｍとした時の入力ロスの例を以下に示す。
［数５］
ａ＝−１７ｄＢ＝１０^−１７
ｂ＝−２７ｄＢ＝１０^−２７
ｃ＝−２４ｄＢ＝１０^−２４
ｄ＝−３４ｄＢ＝１０^−３４ Thus, the intensity x of the downstream optical signal λ1 and the intensity Y of the upstream optical signal λ2 can be calculated by the following equations, respectively.
[Equation 4]

An example of input loss when the wavelength λ1 of the downstream optical signal is 1.49 μm and the wavelength λ2 of the upstream optical signal is 1.31 μm is shown below.
[Equation 5]
a = ⁻¹⁷ dB = 10 ⁻¹⁷
b = ⁻²⁷ dB = 10 ⁻²⁷
c = −24 dB = 10 ⁻²⁴
d = ⁻³⁴ dB = 10 ⁻³⁴

  As described above, when the wavelengths of the downstream optical signal and the upstream optical signal are determined in advance and the same number of detectors as the number of wavelengths are arranged, the measurement conditions of the detector are changed. The intensity of each optical signal can be calculated without any problem.

  As described above, according to the optical fiber identification device and the determination method of the present invention, it is possible to obtain a measurement value obtained by changing the measurement conditions according to the number of wavelengths of the optical signal transmitted through the optical transmission line. Thus, it is possible to determine whether or not there is an optical signal of each wavelength passing through the optical transmission line. In particular, for optical signals having two or more wavelengths that pass through the optical transmission line at different wavelengths in the vertical direction, it is possible to determine the intensity and direction of the optical signal for each wavelength with high accuracy. .

  In addition, the description in this Embodiment shows an example of the optical-core-line discrimination | determination apparatus and discrimination | determination method based on this invention, and is not limited to this. The detailed configuration and detailed operation of the optical fiber determination device and the determination method in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

It is the top view which expanded and displayed the optical fiber line discriminating device concerning the embodiment of the present invention partially. It is a top view which shows the whole optical core discriminating device which concerns on embodiment of this invention. It is a figure for demonstrating the method of changing and measuring the measurement conditions of a detector. It is a figure explaining the optical fiber discriminating method concerning another embodiment of the present invention. It is a block diagram which shows an example of a PON communication system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical fiber core wire 100 Optical fiber core discriminating device 110 Bending fixed part 111 Guide groove 112 Bending holding part 113 Movable press part 121,122 Detector 123 Optical filter 130 Discrimination processing part

900 Communication System 901 OLT
902 Splitter 903 ONU

Claims (9)

An optical fiber discriminating device for detecting the intensity and transmission direction of optical signals having two or more different wavelengths transmitted through an optical fiber,
A bending fixing portion for bending and fixing the optical fiber core wire in order to leak the optical signal from the optical fiber core wire;
A detector for measuring leakage light from the optical fiber core bent at the bending fixing part;
A determination processing unit that inputs measurement data from the detector and determines the intensity and transmission direction of each of the optical signals; and
The detector measures the leakage light by changing measurement conditions by twice the number of wavelengths of the optical signal,
The discrimination processing unit is measured by the detector based on a ratio of leakage from the optical fiber core wire (hereinafter referred to as input loss) determined in advance depending on a measurement position of the detector and the wavelength. In addition, the optical fiber identification device is configured to determine the intensity and transmission direction of the optical signal from the intensity of the leaked light. The optical fiber identification device according to claim 1, wherein the measurement condition is determined by the measurement position and a light receiving condition of the detector. 3. The light according to claim 1, wherein the measurement condition is that the measurement position is two different points, and the light reception condition of the detector is changed by the number of wavelengths at each of the measurement positions. Core wire discrimination device. The optical fiber identification device according to claim 1, wherein the measurement condition is that the measurement position is changed by twice the number of wavelengths. The measurement conditions and the light receiving conditions are changed so that the product of the number of the measurement positions and the number of the light receiving conditions is twice the number of wavelengths. The optical fiber identification device according to claim 2. 3. The optical fiber discriminating apparatus according to claim 1, wherein the light receiving condition is changed by changing a type of a light receiving element of the detector. 3. The optical fiber discriminating apparatus according to claim 1, wherein the light receiving condition is changed by changing a wavelength selecting function provided in the detector. The wavelength selection function is an optical filter provided in front of the detector, and the wavelength selection function is changed by changing a wavelength characteristic of the optical filter. The optical fiber identification device according to claim 2. An optical fiber identification method for detecting the intensity and transmission direction of optical signals having two or more different wavelengths transmitted through an optical fiber,
Partially bending the optical fiber core;
Measure the intensity of leaked light from the bent optical fiber core while changing the measurement conditions by twice the number of wavelengths of the optical signal,
The optical signal is determined from the measured intensity of the leaked light based on the ratio of leakage from the optical fiber core (hereinafter referred to as input loss) determined in advance depending on the measurement position of the leaked light and the wavelength. A method for discriminating optical fiber, comprising discriminating the intensity and transmission direction of the optical fiber.

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