JP2001024590A - Optical transmission line monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical transmission line monitor device in which it can be easily confimed by visual observation whether a signal is transmitted through an optical fiber or not. SOLUTION: Part of an optical signal transmitted from an optical fiber 1A to an optical fiber 1B is branched by an optical branching filter 20 and the branched signal is converted into voltage VA by a phototransistor(PT) 32A and the voltage VA is applied to a voltage comparator 34A. When the voltage VA is higher than reference voltage Vref, an optical detection signal DET is outputted from the comparator 34A. The signal DET is given to a display signal generation part 35A, a display signal IND is generated and an FED 36A is turned on by the display signal IND.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission line monitoring apparatus used for, for example, a line connection board for an optical cable and for monitoring whether an optical signal is transmitted on an optical transmission line. .

[0002]

2. Description of the Related Art Conventionally, a line connection board for an optical cable has a configuration and a function that can be said to be an extension of a line connection board for a metallic cable. That is, one or a plurality of optical cables drawn into the line connection board for optical cables are separated into a plurality of optical fibers constituting the optical cables, and are connected to optical connectors provided for each optical fiber. Then, by connecting the optical connectors to which each optical fiber is connected with an optical jumper wire composed of optical fibers having optical connectors connected to both ends, arbitrary optical fibers of the optical cable are connected to each other. Can be performed.

[0003]

However, the conventional line connection board for optical cables has the following problems. For example, in a line connection panel for a metallic cable, by connecting a measuring instrument such as a tester or an oscilloscope to the terminal to which the cable core pair is connected, the signal transmitted on the line can be easily connected without affecting the signal. The signal on the line can be monitored. On the other hand, in a line connection board for an optical cable, the optical fibers are connected to each other by an optical jumper via an optical connector, so that the signals transmitted on the line are not affected and the signals on the line are not affected. A measuring instrument for monitoring the signal could not be connected. For this reason, it is not possible to check whether or not a signal is actually transmitted to each optical fiber, causing an artificial line failure accident such as accidentally disconnecting an operating line when a connection is changed. There was a fear. An object of the present invention is to solve the problems of the prior art and to provide an optical transmission line monitoring device capable of easily visually checking whether or not a signal is transmitted on an optical fiber. .

[0004]

According to a first aspect of the present invention, there is provided an optical transmission line monitoring apparatus, wherein first and second optical fibers in an optical transmission line are respectively connected. Optical splitting means having first and second terminals for splitting a part of an optical signal transmitted between the first and second terminals and outputting the split signal to a split output terminal; Optical / electrical conversion means for detecting an optical signal output from the branch output terminal and outputting an electric signal of a level corresponding to the intensity of the optical signal; and the optical / electrical conversion means And an optical detection means for outputting an optical detection signal indicating that an optical signal is being transmitted to the optical transmission line when the level of the electrical signal exceeds a certain value. Have. According to the first aspect, since the optical transmission line monitoring device is configured as described above, the following operation is performed. When an optical signal is transmitted between the first and second optical fibers in the optical transmission line, a part of the optical signal is branched by the optical branching unit and output to the branch output terminal. The optical signal output from the branch output terminal is detected by the optical / electrical conversion means, and is converted into an electric signal of a level corresponding to the intensity of the optical signal. The level of the electric signal is determined by the light detecting means. If the level exceeds a certain value, a light detection signal indicating that the optical signal is being transmitted is output.

According to a second aspect of the present invention, the optical branching means in the optical transmission line monitoring device according to the first aspect of the present invention outputs a part of an optical signal transmitted from the first terminal to the second terminal by branching it. And a second branch output terminal for branching and outputting a part of the optical signal transmitted from the second terminal to the first terminal. According to the second aspect, the following operation is performed. An optical signal between the first and second optical fibers in the optical transmission line is branched by an optical branching unit in each direction, and a part of the optical signal in each direction is output to the first and second branch output terminals. . This first
And the optical signal output from the second branch output terminal is
The electric signal is detected by the electric conversion means and converted into an electric signal of a level corresponding to the intensity of the optical signal. The level of the electric signal is determined by the light detecting means. If the level exceeds a certain value, a light detection signal indicating that the optical signal is being transmitted is output. According to a third aspect, in the optical transmission line monitoring device of the first or second aspect, an external output terminal for outputting an electric signal output from the optical / electrical conversion means to the outside is provided. Thus, the state of the signal on the line can be easily monitored without affecting the signal transmitted on the line by connecting the measuring instrument to the external output terminal.

According to a fourth aspect, in the optical transmission line monitoring device according to the first to third aspects, an optical signal is transmitted to the optical transmission line based on the optical detection signal output from the optical detection means. Display means for displaying whether or not the user is in a visible state. Thereby, the light detection signal is given to the display means, and based on the light detection signal, whether or not the light signal is being transmitted to the light transmission path is visually displayed. According to a fifth aspect of the present invention, the display means in the optical transmission line monitoring device according to the fourth aspect of the present invention continues to display, for a predetermined time, that the optical signal is transmitted to the optical transmission line even after the light detection signal is stopped. It is configured to do so. Accordingly, when the light detection signal is output from the light detection means, a visual indication that the light signal is being transmitted to the light transmission path is displayed by the display means, and after the output of the light detection signal is stopped. Also, the display indicating that the optical signal is being transmitted is continuously performed for a predetermined time. Therefore, even in an optical transmission line where an optical signal is intermittently transmitted, an indication that an optical signal is being transmitted is always displayed as long as the optical signal is detected intermittently.

[0007]

FIG. 1 is a block diagram of an optical transmission line monitoring apparatus showing an embodiment of the present invention. This optical transmission line monitoring device is provided, for example, along with a line connection panel for an optical cable,
It is used by being incorporated into this optical cable line connection board,
This device is inserted in the middle of an optical fiber, which is an optical transmission line, to monitor an optical signal transmitted on the optical fiber. This optical transmission line monitoring device includes an optical connector 11A on the device side for connecting the optical connector 2A on the optical fiber 1A side so as to be inserted between the optical fibers 1A and 1B constituting the transmission line 1 to be monitored. An optical connector 11B on the device side for connecting the optical connector 2B on the optical fiber 1B side. One ends of optical fibers 12A, 12B are connected to the optical connectors 11A, 11B, respectively, and the other ends of the optical fibers 12A, 12B are connected to terminals 21A, 21A of an optical branching unit (for example, an optical splitter) 20. 21B.

The optical demultiplexer 20 is used to input and output optical signals.
In addition to the two terminals 21A and 21B, two branch output terminals 22A and 22A for branching and outputting a part of the optical signal.
2B. Then, most of the optical signal input from the terminal 21A is output to the terminal 21B, and part of the optical signal is output to the branch output terminal 22A. In addition, most of the optical signal input from the terminal 21B is output to the terminal 21A, and part of the optical signal is output to the branch output terminal 22B. Optical / electrical conversion means (for example, a phototransistor, hereinafter, referred to as “PT”) 32 are connected to branch output terminals 22A, 22B of the optical demultiplexer 20 via optical fibers 31A, 31B, respectively.
A and 32B are connected. PT32A, 32B
The optical signals output from the branch output terminals 22A and 22B are detected, and electric signals (in this case, voltages) VA and VB having levels corresponding to the intensities of the optical signals are output.

The output sides of the PTs 32A and 32B are connected to external output terminals 33A and 33B for outputting voltages VA and VB corresponding to the intensity of the optical signal to the outside, respectively, and are connected to light detecting means (for example, a voltage comparison circuit). 34A, 34B
Are connected to the first input side of The voltage comparator 34A,
34B is a second reference voltage Vref.
, And the voltages VA and VB applied from the PTs 32A and 32B to the first input side are equal to the reference voltage V
ref, a light detection signal DET is output to the output side.
Is output. The output sides of the voltage comparators 34A and 34B are connected to the input sides of the display signal generators 35A and 35B, respectively. Display signal generators 35A and 35B
Is a period during which the light detection signal DET is given and a predetermined time (for example, 5 seconds) after the stop of the light detection signal DET;
It outputs the display signal IND. For example, the display signal generation unit 35A is connected to inverters 35a and 35b that delay the light detection signal DET given from the voltage comparator 34A and outputs a delayed light detection signal DLY, and is connected to the output side of the inverter 35a and outputs the light detection signal DET. A monostable multivibrator (monostable circuit) 35c that outputs a monopulse signal PLS for 5 seconds from the falling point of the signal, and a logical OR gate 35d that generates a display signal IND by calculating a logical sum of these three signals. It is composed of Display means (for example, light emitting diodes, hereinafter, referred to as “LEDs”) are provided on the output sides of the display signal generation units 35A, 35B, respectively.
36A and 36B are connected. LED 36A, 36
B is turned on by the display signal IND, and the optical fiber 1
In this case, whether or not an optical signal is being transmitted is displayed in a visible state.

FIG. 2 is a schematic sectional view showing an example of the structure of the optical demultiplexer 20 in FIG. The optical demultiplexer 20 reinforces the optical fiber 12A connected to the terminal 21A side and performs ferrule 23A for accurate alignment.
have. The ferrule 23A is a tubular member formed of a light-transmitting material such as glass, and is adapted to insert and fix the optical fiber 12A into a hole at the center. The outer dimensions of the ferrule 23A and the positions and inner diameters of the holes are made extremely precisely in order to reduce the coupling loss due to the displacement of the optical fiber 12A. Optical splitter 20
Has a ferrule 23B similar to the ferrule 23A for connecting the optical fiber 12B on the terminal 21B side. After the optical fibers 12A and 12B are inserted into the ferrules 23A and 23B and fixed with an adhesive or the like, the ferrules 2 are adjusted so that the end faces thereof are exactly 45 °.
Polished together with 3A and 23B.

The optical demultiplexer 20 includes optical fibers 12A and 12A.
The ferrule 23A has a sleeve 24 for positioning the ferrules 23A and 23B to be connected so that the end faces thereof accurately contact the surface. The sleeve 24 is formed of a cylindrical elastic metal having an inner diameter slightly smaller than the outer diameter of the ferrules 23A and 23B, and has a slit provided along the central axis of the cylinder. The ferrules 23A and 23B are inserted from both ends of the sleeve 24, and the ferrules 23A and 23B are tightly fixed by a spring effect to reduce connection errors. Ferrules 23A, 23 to which optical fibers 12A, 12B are connected
The end surfaces of 3B are in surface contact with each other with the inter-branch film 25 interposed in the sleeve 24 so that no gap is formed. The branching film 25 is formed of a dielectric multilayer film or the like, and is for transmitting most optical signals and reflecting some optical signals. Since the end faces of the ferrules 23A and 23B are polished so as to contact at an angle of exactly 45 °, a part of the optical signal in the optical fibers 12A and 12B will be reflected by the branching film 25 in the perpendicular direction. It has become.

The sleeve 24 has holes 24a and 24b through which the optical signal reflected by the branching film 25 passes. Outside the holes 24a and 24b of the sleeve 24, an optical fiber 31 is provided on the optical path of the reflected optical signal.
Sleeves 26A and 26B for connecting A and 31B are arranged. The optical fiber 31A connected to the terminal 22A of the optical splitter 20 is reinforced by a ferrule 27A and inserted into the sleeve 26A. The optical fiber 31B connected to the terminal 22B side
Are reinforced by a ferrule 27B and inserted into the sleeve 26B. These optical fibers 31
A and 31B are inserted into the ferrules 27A and 27B, respectively, fixed with an adhesive or the like, and then polished so that the end faces thereof are exactly right angles.

Next, the operation will be described. An optical signal transmitted from the optical fiber 1A in the direction of the optical fiber 1B is guided to the terminal 21A of the optical demultiplexer 20 through the optical connectors 2A and 11A and the optical fiber 12A. Most of the optical signal input to the terminal 21A of the optical demultiplexer 20
The light is output to the terminal 21B through the zero-branching film 25, and is output to the optical fiber 1B through the optical fiber 12B and the optical connectors 11B and 2B. Terminal 21 of optical demultiplexer 20
A part of the optical signal input to the terminal A is reflected by the branching film 25 of the optical demultiplexer 20, passes through the transparent ferrule 23A, and the hole 24a provided in the sleeve 24, and passes through the terminal 22.
The light enters the A-side optical fiber 31A. Optical fiber 31
The optical signal incident on A is guided to PT32A and converted into a voltage VA corresponding to the intensity of the optical signal. PT32
The voltage VA output from A is output to the external output terminal 33A and also applied to a first input side of the voltage comparator 34A. A reference voltage Vref is provided to a second input side of the voltage comparator 34A, and the voltage VA is equal to the reference voltage Vr.
If it is higher than ef, a light detection signal DET is output from the output side of the voltage comparator 34A. If the voltage VA is equal to or lower than the reference voltage Vref, the light detection signal DET is not output from the output side of the voltage comparator 34A.

The light detection signal DET output from the voltage comparator 34A is provided to a display signal generator 35A. When the light detection signal DET is input to the display signal generation unit 35A,
While the light detection signal DET is being input, the display signal I
ND is generated, and the display signal IND is continuously generated and output for 5 seconds even after the input of the light detection signal DET is stopped. The display signal IND output from the display signal generation unit 35A is given to the LED 36A,
The ED 36A lights up. In the optical transmission line monitoring apparatus, the same operation is performed for an optical signal transmitted from the optical fiber 1B to the optical fiber 1A. That is, the terminal 21B of the optical demultiplexer 20 is passed from the optical fiber 1B through the optical connectors 2B and 11B and the optical fiber 12B.
Most of the optical signal guided to the optical splitter 20 passes through the coupling / branching film 25 of the optical splitter 20, is output to the terminal 21A, and is output to the optical fiber 1A through the optical fiber 12A and the optical connectors 11A and 2A. .

At this time, part of the optical signal input to the optical demultiplexer 20 is reflected by the branching film 25 and is
B, and passes through a hole 24b provided in the sleeve 24 and enters the optical fiber 31B. The optical signal incident on the optical fiber 31B is guided to the PT 32B and converted into a voltage VB corresponding to the intensity of the optical signal. The voltage VB output from the PT 32B is output to the external output terminal 33B, and the reference voltage Vref is output by the voltage comparator 34B.
Is compared to If the voltage VB is higher than the reference voltage Vref, the light detection signal D is output from the output side of the voltage comparator 34B.
ET is output. The light detection signal DET output from the voltage comparator 34B is provided to the display signal generation unit 35B.
A display signal IND that continues for 5 seconds after the stop of the light detection signal DET is generated. Display signal IND is LED36B
And the LED 36B is turned on.

As described above, the optical transmission line monitoring apparatus of the present embodiment has the following advantages (1) to (5). (1) Since the optical demultiplexer 20 is inserted into the transmission path to extract a part of the optical signal, the optical signal on the transmission path can be constantly monitored. (2) Since the optical demultiplexer 20 can take out the optical signal in each direction, it is possible to constantly monitor the optical signal on the transmission line in each direction. (3) LEDs 36A and 36B for indicating the presence or absence of an optical signal
Therefore, the presence or absence of an optical signal on the transmission path can be easily visually checked without using a measuring instrument or the like. This eliminates the risk of accidentally disconnecting the line in operation. Further, since the use status can be easily confirmed, the work efficiency such as the connection change work is improved. (4) Since the external output terminals 33A and 33B for outputting the output voltages VA and VB of the PTs 32A and 32B to the outside are provided, by connecting a measuring instrument or the like, the output can be easily performed without affecting the line. The status of the signal on the line can be monitored. (5) The display signal generator 35 continuously outputs the display signal IND for a predetermined time after the stop of the light detection signal DET.
A, 35B. Accordingly, even in an optical transmission line where an optical signal is intermittently transmitted, as long as the optical signal is intermittently detected, it is possible to always display that the optical signal is being transmitted. In addition, it is possible to eliminate a possibility that the line in operation is disconnected by mistake.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, there are the following modifications (a) to (h). (A) Although the optical transmission line monitoring device of FIG. 1 is for one line, an optical transmission line monitoring device for a plurality of lines can be configured by providing a plurality of similar optical transmission line monitoring devices. (B) The configuration of the optical demultiplexer 20 is not limited to the configuration illustrated in FIG. As long as a part of the optical signal on the transmission line can be branched and output, any configuration can be similarly applied. (C) The optical signal in the optical fiber 1 is monitored for each direction. In the case of a unidirectional optical fiber, the optical signal in only the transmission direction may be monitored.

(D) Two LEDs 36A and 36B are provided for each direction so that monitoring of the bidirectional transmission path can be performed separately. When one LED has an abnormality in either direction, an abnormality display is made. It may be performed. (E) The external output terminals 34A and 34B can be omitted. (F) When an optical signal is continuously transmitted through the optical fiber 1, for example, the display signal generating unit 35 is used to simplify the circuit.
A and 35B can be omitted. (G) A photodetector such as a photodiode can be used instead of the PTs 32A and 32B. (H) LED 36A, 36B when optical signal is detected
Is turned on, but the LEDs 36A and 36B may be turned on when no light signal is detected.

[0019]

As described above in detail, according to the first aspect, the optical branching means for branching and outputting a part of the optical signal transmitted on the optical transmission line, and the optical branching means. Optical / electrical conversion means for converting the obtained optical signal into an electric signal; and light detection means for detecting the presence or absence of the optical signal based on the level of the electric signal. Thereby, there is an effect that it is possible to easily monitor whether or not the optical signal is transmitted on the optical fiber. According to the second invention, the optical branching unit is configured to branch a part of the optical signal transmitted on the optical transmission line for each direction and output the branched signal. Accordingly, in addition to the effect of the first aspect, there is an effect that the presence or absence of the optical signal transmitted on the optical fiber can be monitored for each direction. According to the third aspect, an external output terminal for outputting an electric signal output from the optical / electrical conversion unit to the outside is provided. As a result, the state of the optical signal on the line can be easily monitored by the measuring instrument without affecting the line, so that in addition to the effects of the first and second inventions, the state of the line can be more accurately determined. There is an effect that can be known.

According to the fourth aspect, the display means for displaying the light detection signal output from the light detection means in a visible state is provided. Thereby, in addition to the effects of the first to third aspects, there is an effect that it is possible to easily visually check whether or not the optical signal is transmitted on the optical fiber.
According to the fifth aspect, the display means is configured to continue to display that the optical signal is being transmitted for a predetermined time even after the optical detection signal is stopped. As a result, even in an optical transmission line where an optical signal is intermittently transmitted, as long as the optical signal is intermittently detected, an indication that the optical signal is being transmitted is always displayed. In addition to the effects of the invention of the third aspect, there is an effect that it is possible to eliminate the possibility that the line in operation is accidentally disconnected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical transmission line monitoring device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an example of the structure of the optical demultiplexer 20 in FIG.

[Explanation of symbols]

 1A, 1B Optical fiber 20 Optical splitter 21A, 21B Terminal 22A, 22B Branch output terminal 23A, 23B Ferrule 24 Sleeve 25 Combined branch film 32A, 32B PT (Phototransistor) 33A, 33B External connection terminal 34A, 34B Voltage comparator 35A, 35B Display signal generator 36A, 36B LED (light emitting diode)

Claims (5)

[Claims] 1. An optical transmission line comprising first and second terminals to which first and second optical fibers are connected, respectively.
An optical branching means for branching a part of the optical signal transmitted between the first and second terminals and outputting the branched signal to a branch output terminal; connected to a branch output terminal of the optical branching means; An optical / electrical conversion means for detecting an output optical signal and outputting an electric signal of a level corresponding to the intensity of the optical signal; an electric signal output from the optical / electrical conversion means being provided; An optical detection means for outputting an optical detection signal indicating that an optical signal is being transmitted to the optical transmission line when the level of the optical transmission line exceeds a certain value. . 2. The first branch output terminal for branching and outputting a part of an optical signal transmitted from the first terminal to the second terminal, and the second terminal. And a second branch output terminal for branching and outputting a part of the optical signal transmitted from the first terminal to the first terminal.
An optical transmission line monitoring device according to claim 1. 3. The optical transmission line monitoring device according to claim 1, further comprising an external output terminal for outputting an electric signal output from the optical / electrical conversion unit to the outside. 4. A display unit for displaying whether or not an optical signal is being transmitted to the optical transmission line based on the optical detection signal output from the optical detection unit. The optical transmission line monitoring device according to claim 1, 2 or 3, wherein: 5. The display device according to claim 4, wherein the display means continues to display for a predetermined time that the optical signal is being transmitted to the optical transmission line even after the optical detection signal is stopped. An optical transmission line monitoring device according to claim 1.