JP3882724B2 - Optical fiber discrimination device and discrimination method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical core discriminating apparatus and an optical core discriminating method used for performing optical fiber line contrast, live line determination, and the like.
[0002]
[Prior art]
In laying an optical cable or the like, in order to measure the optical loss of a plurality of optical fiber cores housed in the cable, it is necessary to identify and identify the optical fiber core wires. Usually, optical fiber cores are identified by sending a special optical signal (for example, an optical signal modulated to a frequency of 270 Hz) from one end of the optical cable, and detecting the received light by the light receiving element at the other end. The determination is made by the detection circuit. In the detection of the optical signal by the light receiving element, the optical fiber is partially bent, and leaked light generated by the bending is received and detected (for example, see Patent Document 1).
[0003]
Moreover, a hand-type device is known as a device for discriminating an optical fiber core wire (see, for example, Patent Document 2). FIG. 1 is a diagram showing an example of an optical core discriminating apparatus, although the shape is different from that described in Patent Document 2. FIG. 1A is a diagram showing a state when an optical fiber core wire is set, and FIG. 1B is a diagram showing an operating state during determination. In the figure, 1 is an optical fiber, 2 is a body portion, 3 is a head portion, 4 is a semicircular protruding portion, 5 is a guide groove, 6 is a movable portion, 7 is an operation knob, 8 is a display portion, and 9 is a display portion. A reset button is shown.
[0004]
The optical fiber identification device illustrated in FIG. 1 has a head portion 3 on the distal end side of the main body portion 2 and is configured to be slidable with a movable portion 6 facing the head portion 3. The head portion 3 has a semicircular protruding portion 4 protruding toward the movable portion 6, and the protruding portion 4 is provided with a guide groove 5 for storing the optical fiber 1 by bending it. The movable portion 6 includes a display portion 8 having a display lamp or the like disposed on the surface, a reset button 9 and the like, and pushes the integrally provided operation knob 7 forward so that the non-operating state of FIG. The operating state shown in FIG.
[0005]
The distal end portion of the movable portion 6 is formed as a concave portion having a shape that fits the convex portion 4, and one light receiving element or two light receiving elements (not shown) are disposed in the concave portion. In the state of FIG. 1A, the optical fiber 1 is accommodated along the guide groove 5 of the protruding portion 4, and the optical fiber 1 is bent. Next, the operation knob 7 is pushed out to be in the operation state shown in FIG. 1B, the external light is blocked, and the leaked light from the optical fiber 1 bent by the head portion 3 is received and detected by the light receiving element. The detected leaked light is amplified and discriminated by a detection circuit (not shown) provided in the main body 2 and the movable part 6 and transmitted through the optical fiber by the display unit 8 or a buzzer (not shown). The presence or absence of an optical signal is displayed.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 09-178945 [Patent Document 2]
Japanese Patent Laid-Open No. 08-110416
[Problems to be solved by the invention]
Let's detect the live state of the optical transmission line called PDS (Passive Double Star) communication or PON (Passive Optical Network) communication as shown in FIG. And In PDS (PON) communication, a downstream optical signal λ1 from an OLT (telephone optical line terminal) is branched by a splitter and transmitted to a plurality of ONUs (user home optical network units). Each ONU 1 to ONU 4 selects and acquires only the optical signal addressed to itself. The downstream optical signal λ1 includes a signal for controlling the transmission timing of the upstream optical signal λ2 from each of the ONU1 to ONU4.
[0008]
From each of the ONU1 to ONU4, an upstream optical signal λ2 is transmitted at a transmission timing designated by the OLT. Each optical signal λ2 sent from each of the ONU1 to ONU4 enters the OLT with a signal string T that is coupled by a splitter and has a timing specified by the OLT. In the OLT, the signal sequence T of the upstream optical signal λ2 is divided into optical signals for the ONU1 to ONU4.
[0009]
Here, for example, there is an application for abolition of OUN1, and an attempt is made to remove the line between the splitter and OUN1. In this case, the determination of which port of the splitter is connected to OUN1 is normally made at point X on the splitter exit side. In practice, this is done by opening a closure for connecting and branching optical cables. If the above-described optical fiber identification device is used for this line determination, the upstream optical signal λ1 from the OLT side is transmitted even if the optical signal λ2 is not transmitted after the power of OUN1 is turned off. The leakage light of the optical signal λ1 is detected and regarded as a live line state, and the line of OUN1 cannot be specified.
[0010]
Also, a special optical signal (for example, an optical signal modulated to a frequency of 270 Hz) different from the optical signals λ1 and λ2 is placed in the line from the OUN1 side, and the leaked light is detected at point X to contrast the lines. It is possible. However, it is necessary to prepare an expensive light source device that transmits modulated light having a special wavelength to the OUN1 side, and the modulated light may enter the OLT and have an adverse effect, which is not practical. Further, the level of leakage light received by the two light receiving elements provided on the left and right sides is compared, the direction of the optical signal is detected, and the optical signal λ1 from the OUN1 side or the optical signal λ2 from the OLT side Although a method for determining whether or not there is a possibility is considered, it is easily influenced by disturbance light or the like, and an accurate determination cannot be desired.
[0011]
The present invention has been made in view of the above-described circumstances, and can detect the presence or absence of an optical signal in an optical transmission line without using a light source device having a special wavelength, and can determine a specific core wire. It is another object of the present invention to provide an optical core discriminating apparatus and a discriminating method capable of discriminating the presence or absence of a specific optical signal without affecting the optical transmission state of the working line in PDS (PON) communication.
[0012]
[Means for Solving the Problems]
An optical fiber core discriminating device according to the present invention includes a bend imparting unit that partially leaks an optical fiber to leak an optical signal, a light receiving element that detects leaked light, and a detection circuit that amplifies and discriminates the received leaked light. Further, the optical fiber identification device has at least two light receiving elements, and includes a wavelength selection filter having a different wavelength range on each light receiving surface side.
[0013]
In addition, the optical fiber identification method according to the present invention is such that an optical fiber is partially bent by a bend applying unit to leak an optical signal, the leaked light is detected by a light receiving element, and the detected leaked light is amplified by a detection circuit. an optical cord determination method of, at least two detected for each wavelength of the optical signal by the light receiving element the leakage light through the different wavelength selective filters wavelength range arranged on each of the light-receiving surface side of the light-receiving element It is what you do.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an example of an optical core discriminating apparatus used in the description of the prior art, FIG. 2 (A) is a diagram showing an example of the present invention, and FIG. 2 (B) is a diagram showing another example of the present invention. It is. In the figure, 1 is an optical fiber, 10 is a bending portion, 11 is a light receiving element, 12, 12a and 12b are wavelength selection filters, and 13 is a detection circuit.
[0015]
The optical-core-line discriminating device according to the present invention can be configured in a shape as shown in FIG. That is, the optical fiber identification device has a head portion 3 on the distal end side of the main body portion 2 and is configured to be slidable with the movable portion 6 facing the head portion 3. The head portion 3 has a semicircular protruding portion 4 protruding toward the movable portion 6, and the protruding portion 4 is provided with a guide groove 5 for bending and storing the optical fiber 1.
[0016]
The movable portion 6 has a display portion 8, a reset button 9, and the like on the surface, and pushes the operation knob 3 that is integrally provided forward so that the non-operating state of FIG. It can be in an operating state. When in the operating state, external light is shielded, and light leaked from the optical fiber 1 that is bent by being housed in the guide groove 5 of the head portion 3 is detected by the light receiving element 11 (see FIG. 2). The detected leaked light is amplified and discriminated by a detection circuit 13 (see FIG. 2) provided in the main body 2 and the movable unit 6, and the result is displayed by the display unit 8 or a buzzer (not shown). .
[0017]
The distal end portion of the movable portion 6 is formed as a concave portion having a shape that fits the convex portion 4, and forms a bend imparting portion 10 of the optical fiber 1 as shown in FIG. For example, two light receiving elements 11 are arranged on the left and right sides of the concave portion on the movable portion 6 side, and approach the optical fiber 1 bent by the bending applying portion 10 to receive the leaked light from the optical fiber 1. To detect. The light receiving element 11, by using two light receiving elements 11, it becomes possible direction discrimination signal light. That is, in the bending imparting unit 10, the leakage light detected in the first bend is larger than the leakage light detected in the next bend, and by comparing the level of the leakage light that can be detected by the two light receiving elements 11. The optical signal direction can be determined.
[0018]
In the present invention, leakage light of the optical fiber 1 is received through the wavelength selection filter 12 on the light receiving surface side of the light receiving element 11. As the wavelength selection filter 12, for example, various filters such as a dielectric multilayer film can be used. By disposing the wavelength selection filter 12 on the light receiving surface side of the light receiving element 11 or the like, it becomes possible to detect only an optical signal having a specific wavelength that leaks at the bending portion 10. That is, in wavelength multiplexing communication, it is possible to detect the presence or absence of an optical signal in a specific wavelength band.
[0019]
In the present invention, as shown in FIG. 2B, at least two light receiving elements 11 are provided, and wavelength selection filters 12 a and 12 b having different wavelengths are disposed on the light receiving surface side of each light receiving element. be able to. Thus, for example, can only detect light right side of the wavelength λa the light receiving element 11 of FIG., It is possible to make only able to detect light receiving element 11, the wavelength λb of the left side. In addition, it can also be set as the structure which does not arrange | position a wavelength selection filter in any one light receiving element.
[0020]
The detection circuit 13 includes switching means for switching the detection of the wavelength λa and the wavelength λb, and can discriminate between optical signals of two different wavelengths, and can also check the presence or absence of the optical signal. The number of light receiving elements 11 is not limited to two, and three or more light receiving elements 11 may be provided, and wavelength-multiplexed optical transmission is performed by switching the detection by disposing wavelength selection filters having different selection wavelengths in each light receiving element. It is also possible to select an optical signal in a specific wavelength band from the line and examine the presence or absence of the optical signal.
[0021]
2 is used to perform the core line discrimination at the X point on the exit side of the splitter while maintaining the current communication state on the PDS (PON) communication line of FIG. Suppose you use it. The wavelength selection filter 12 is assumed to be capable of selecting the wavelength band of the upstream optical signal λ2. For example, there is an application for abolition of OUN1, and the core wire of OUN1 is determined at the point X on the exit side of the splitter in order to remove the splitter-OUN1 line.
[0022]
In this case, it is assumed that the ONU 1 is powered off and is not in use, and the OLT and ONU2 to ONU4 are in normal use. Since the wavelength selection filter 12 is selected so as to transmit only the wavelength of the upstream optical signal λ2, the downstream optical signal λ1 from the OLT is not detected. Further, since the upstream optical signal λ2 is not transmitted from the ONU 1, the upstream optical signal λ2 is not detected at the point X. As a result, no optical signal is detected at the point X, and it can be specified that it is the core of the ONU1 line. In the other ONU2 to ONU4, the upstream optical signal λ2 is detected and determined to be in the live state. For safety reasons, the upstream signal λ2 is detected at point X when the ONU1 side is turned on, and the upstream optical signal λ2 is not detected at point X when the ONU1 side is turned off again. It is good to confirm.
[0023]
Further, the optical fiber identification device configured as shown in FIG. 2B performs the optical fiber identification at the exit X point of the splitter while maintaining the current communication state with the PDS (PON) communication line of FIG. Suppose it was used for For example, one wavelength selection filter 12a can detect the upstream optical signal λ2, and the other wavelength selection filter 12b can detect the downstream optical signal λ1. Similarly to the above, there is an application for abolition of OUN1, and in order to remove the line from splitter to OUN1, the core wire of OUN1 is determined at point X at the exit of the splitter.
[0024]
In this case, it is assumed that the ONU 1 is turned off and is not in use, and the OLT and the other ONUs 2 to 4 are in normal use. The downstream optical signal λ1 from the OLT is detected by the wavelength selective filter 12b side at the X point of the ONU1 line, and the communication line is determined to be in the live line state. However, since the upstream optical signal λ2 is not transmitted from the ONU 1, the optical signal λ2 is not detected on the wavelength selection filter 12a side, and can be specified as the core of the ONU 1 line. For the other ONU2 to ONU4, both the downstream optical signal λ1 and the upstream optical signal λ2 are detected, and it is determined that they are in the live state.
[0025]
【The invention's effect】
As described above, according to the present invention, the presence / absence of an optical signal in a specific wavelength band can be examined, and the core wire can be easily identified. Further, it is possible to determine the presence / absence of an optical signal in a specific wavelength band in wavelength division multiplexing communication. Further, in a PDN (PON) line, the presence / absence of an ONU and a comparison of lines without affecting the communication state of the working line It can be reliably determined at the splitter portion.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of an optical fiber identification device.
FIG. 2 is a diagram illustrating an embodiment of the present invention.
FIG. 3 is a diagram illustrating a PDS (PON) communication line.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical fiber, 2 ... Main-body part, 3 ... Head part, 4 ... Semicircle-shaped protrusion part, 5 ... Guide groove, 6 ... Movable part, 7 ... Operation knob, 8 ... Display part, 9 ... Reset button, DESCRIPTION OF SYMBOLS 10 ... Bending provision part, 11 ... Light receiving element, 12, 12a, 12b ... Wavelength selection filter, 13 ... Detection circuit.

Claims (3)

An optical fiber discriminating device comprising a bend imparting unit that partially leaks an optical fiber to leak an optical signal, a light receiving element that detects leaked light, and a detection circuit that amplifies and discriminates the received leaked light, An optical core discriminating apparatus comprising at least two light receiving elements and provided with wavelength selection filters having different wavelength ranges on each light receiving surface side. It is leaking optical signal partially bent by the application unit bending an optical fiber and detected by the light receiving element leakage light, an optical core discrimination method for discriminating amplified by the detecting circuit the detected leaked light, at least 2 number of via different wavelength selective filters wavelength range arranged on the light-receiving surface side of the light receiving element, an optical core discriminating method characterized by detecting for each wavelength of the optical signal to the leakage light by the light receiving element . 3. The optical fiber core according to claim 2 , wherein the presence or absence of a user transmission device (ONU) or a line control is determined at a splitter branch side of a passive double star (PDS) or passive optical network (PON) line. How to determine.

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