JP3940631B2 - Optical signal monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
[0002]
The present invention relates to an optical signal monitoring device that is inserted into an optical transmission line such as an optical fiber and monitors an optical signal transmitted through the optical transmission line.
[0003]
[Prior art]
[0004]
Along with the rapid increase in optical communication equipment, new construction of optical transmission lines, expansion, wiring changes, etc. are frequently carried out. Such construction inevitably involves a lot of work on existing optical transmission lines. Therefore, a means for easily grasping the operation status such as whether or not an optical signal is flowing through the optical transmission line is required.
[0005]
Such means are not limited to construction, and even in the operation and maintenance of enormous optical transmission lines, the operation status is automatically monitored, and maintenance personnel check the operation status of each optical transmission line on site. It is also necessary for. In addition, on-site confirmation work is not limited to skilled maintenance personnel, and maintenance personnel with little experience do not have the risk of accidents such as accidental disconnection of lines, and are reliable enough to grasp the operation status. It is desirable to have a high monitoring device.
[0006]
Conventionally, as a technique in such a field, for example, there is one described in Japanese Patent Laid-Open No. 2000-284152.
[0007]
FIGS. 2A and 2B are configuration diagrams of a conventional photodetection device described in the publication.
[0008]
As shown in FIG. 2A, the light detection device 10 has an integral structure housed in a light-shielding housing 11, and optical fibers 1 a and 1 b are provided on both end surfaces of the housing 11. Connection portions 11a and 11b for connecting the optical connectors 2a and 2b are formed. On the side surface of the light detection device 10, LEDs (light emitting diodes) 12 a and 12 b for displaying the state of an optical signal in the optical transmission path, and terminals 13 a and 13 b for supplying power and outputting detection signals are provided. .
[0009]
As shown in the cross section of FIG. 2B, the inside of the housing 11 is provided with a linear through hole 11c between the connecting portions 11a and 11b. Furthermore, a through-hole 11d orthogonal to this is provided at the center of the through-hole 11c.
[0010]
A cylindrical metal sleeve 14 is accommodated inside the through-hole 11c. In the central portion of the sleeve 14, window portions 14 a and 14 b for guiding a part of the optical signal to the through hole 11 d are provided. An optical fiber 16a protected by a ferrule 15a and an optical fiber 16b protected by a ferrule 15b are inserted into the sleeve 14 from both ends thereof.
[0011]
The tips of the optical fibers 16a and 16b are polished precisely at 45 ° together with the ferrules 15a and 15b, and are in surface contact with the branch film 17 in the central window portions 14a and 14b of the sleeve 14. The branch film 17 passes most of the optical signal and reflects part of the optical signal. The reflected optical signal is output from the windows 14 a and 14 b of the sleeve 14 to the through hole 11 d of the housing 11. It has come to be.
[0012]
On one side surface of the housing 11, a circuit board 18 a on which the LEDs 12 a, the terminals 13 a, the determination circuit, and the like are mounted is fixed. On the back surface of the circuit board 18a, a PD (photodiode) 19a is mounted so as to fit in the through hole 11d of the housing 11. Similarly, a circuit board 18b on which the LED 12b, the terminal 13b, the PD 19b, a determination circuit, and the like are mounted is fixed to the other side surface of the housing 11.
[0013]
In such a light detection device 10, most of the optical signal incident from the optical fiber 1 a is transmitted to the optical fiber 1 b through the branch film 17, and a part thereof is reflected by the branch film 17. The light passes through the window 14a provided on the ferrule 15a and the sleeve 14 and enters the PD 19a. The optical signal incident on the PD 19a is converted into a voltage corresponding to the intensity of the optical signal, output to the terminal 13a, and the presence or absence of the optical signal is detected by the determination circuit on the circuit board 18a. And if it determines with an optical signal existing, LED12a will be lighted by the determination circuit.
[0014]
Similarly, the optical signal transmitted in the direction from the optical fiber 1b to the optical fiber 1a is detected by the PD 19b on the circuit board 18b side.
[0015]
[Problems to be solved by the invention]
However, the conventional photodetectors have the following problems.
[0016]
For example, a part of the optical signal reflected by the branch film 17 may be incident on the regular PD 19a and may be reflected inside the housing 11 and go around to the opposite PD 19b. In such a case, since the output signals of the PDs 19a and 19b detect the presence or absence of an optical signal by the respective determination circuits, if the sneak optical signal is strong, the light detected by the PD 19b is also determined as a regular optical signal. There was a risk of lack of accuracy.
[0017]
In addition, since the PDs 19a and 19b for detecting the optical signal and the determination circuit for displaying the detection result and the LEDs 12a and 12b are integrated, the outer dimensions of the housing 11 are inevitably large. The optical connector arranged at high density on the existing optical terminal board could not be used.
[0018]
Further, since the connection portions 11a and 11b to the optical fibers 1a and 1b are both plug-type connectors, they cannot be inserted as an adapter between the existing optical terminal board and the optical fiber.
[0019]
The present invention solves the problems of the prior art, can accurately and reliably measure the direction and intensity of an optical signal, and is installed between an existing optical terminal board mounted at high density and an optical fiber connector. An optical signal monitoring device that can be inserted as an adapter is provided.
[0020]
[Means for Solving the Problems]
[0021]
In order to solve the above problems, a first invention of the present invention is that an optical signal monitoring device is inserted into an optical transmission line and a part of the optical signal transmitted to the optical transmission line is branched. And an optical signal detector that outputs an electrical signal corresponding to the intensity of the detected optical signal from a terminal, and the optical signal detector is connected to the terminal of the optical signal detector via a connection cable. And an optical signal indicator that displays the state of the optical signal in the optical transmission path based on the electrical signal output from the optical signal.
[0022]
  thisThe optical signal detector includes a receptacle-type first connector for connecting a plug-type connector on the optical fiber side in the optical transmission line, and a plug for connecting to the receptacle-type connector on the optical terminal board side in the optical transmission line. A second connector of the mold and an optical signal propagating through the optical fiber connecting the first and second connectors are provided at a predetermined angle with respect to the optical axis of the optical signal, A branching section is provided that allows most of the optical signal to pass through and regularly reflects a part of the optical signal.
[0023]
Further, the optical signal detector detects an optical signal propagated from the first connector to the branching unit and regularly reflected by the branching unit, and outputs an electric signal corresponding to the intensity of the detected optical signal. A first detection unit that detects the optical signal that is propagated from the second connector to the branch unit and is regularly reflected by the branch unit, and outputs an electrical signal corresponding to the intensity of the detected optical signal. From the first detector and the second detector, the first and second light emitters for directly supplying the test light to the second detector, the first detector and the second detector, respectively. A terminal for inputting / outputting an electric signal to be output and an electric signal for driving the first and second light emitting units; the first and second connectors; the terminal; the branching unit; And the second detector, and the first and second light emitters are integrated and assembled. And a housing Mutame.
[0024]
The optical signal display includes an analog / digital (hereinafter referred to as “A / D”) conversion unit that converts an electrical signal supplied from the first and second detection units into a digital value, and the A / D conversion. A discriminating unit for discriminating the propagation direction of the optical signal propagating through the optical fiber based on the intensity of the light converted into a digital value by the unit, the propagation direction discriminated by the discriminating unit and the light in this propagation direction A display unit for displaying the intensity and a test unit for driving the first and second light emitting units of the optical signal detector during the test are provided.
[0025]
  First1'sAccording to the invention, since the optical signal monitoring apparatus is configured as described above, the following operation is performed.
[0026]
For example, a second connector of the optical signal detector is connected to a receptacle-type connector provided on the optical terminal board, and a plug connector on the optical fiber side is connected to the first connector of the optical signal detector. Furthermore, an optical signal indicator is connected to the terminal of the optical signal detector via a connection cable. Thereby, a part of the optical signal transmitted between the optical terminal board and the optical fiber is branched and detected by the optical signal detector. Then, an electrical signal corresponding to the intensity of the detected optical signal is output from the terminal of the optical signal detector and applied to the optical signal display device via a connection cable. In the optical signal display, the state of the optical signal in the optical transmission path is displayed based on the electrical signal output from the optical signal detector.
[0027]
  First2According to the present invention, an optical signal monitoring device is inserted into an optical transmission line, and a part of the optical signal transmitted to the optical transmission line is branched and output. An optical signal detector that detects a part of the optical signal and outputs an electrical signal corresponding to the intensity of the detected optical signal, and the optical transmission line based on the electrical signal output from the optical signal detector And an optical signal display for displaying the state of the optical signal inside.
[0028]
  thisThe optical branching device includes a receptacle-type first connector for connecting a plug-type connector on the optical fiber side in the optical transmission line, and a plug-type for connecting to the receptacle-type connector on the optical terminal board side in the optical transmission line. A second connector and an optical signal propagating through the optical fiber connecting the first and second connectors are provided at a predetermined angle with respect to the optical axis of the optical signal. A branch part that allows most of the optical signal to pass through and a part of which is specularly reflected, and a first through hole that outputs the optical signal propagated from the first connector to the branch part and specularly reflected to the outside, And a housing having a second through hole for outputting the optical signal propagated from the second connector to the branch portion and regularly reflected.
[0029]
The optical signal detector detects an optical signal output from the first through hole of the optical splitter, and outputs an electrical signal corresponding to the intensity of the optical signal; and A second detection unit that detects an optical signal output from the second through hole and outputs an electrical signal corresponding to the intensity of the optical signal. The optical signal indicator includes an A / D conversion unit that converts an electrical signal supplied from the first and second detection units into a digital value, and an intensity of light converted into a digital value by the A / D conversion unit. And a display unit for displaying the propagation direction determined by the determination unit and the intensity of light in the propagation direction. .
[0030]
  First2According to the invention, the following operation is performed.
[0031]
For example, a second connector of the optical branching device is connected to a receptacle-type connector provided on the optical terminal board, and a plug-type connector on the optical fiber side is connected to the first connector of the optical branching device. Further, in order to detect the optical signal output from the optical branching device, the first and second detection portions of the optical signal detector are made to coincide with the first and second through holes of the optical branching device. set. Thereby, a part of the optical signal transmitted between the optical terminal board and the optical fiber is branched by the optical branching device and detected by the optical signal detector. Then, an electrical signal corresponding to the intensity of the detected optical signal is output from the optical signal detector and applied to the optical signal display. In the optical signal display, the state of the optical signal in the optical transmission path is displayed based on the electrical signal output from the optical signal detector.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
[0033]
(First embodiment)
[0034]
FIG. 1 is a configuration diagram of an optical signal monitoring apparatus showing a first embodiment of the present invention.
[0035]
This optical signal monitoring apparatus is inserted between a plug-type connector 1a on the optical fiber 1 side and a receptacle-type connector 2a on the optical terminal board 2 side, and the direction of the optical signal transmitted in the optical transmission line The optical signal detector 20, the optical signal indicator 40, and a connection cable 60 that connects the optical signal detector 20 and the optical signal indicator 40 are configured.
[0036]
Here, the optical terminal board 2 is installed at a wiring station or a relay station, and stores a spare optical fiber or a fusion part which is a space for fusing and connecting optical fibers, The connector is configured with a connector connecting part for easily performing wiring connection and wiring change. In the connector connecting portion, a plurality of receptacle-type connectors 2a are arranged in parallel so that a large number of optical fibers can be connected.
[0037]
The optical signal detector 20 divides and detects a part of the optical signal transmitted to the optical transmission line, and outputs an electric signal corresponding to the intensity of the detected optical signal. A receptacle-type connector 21 for inserting the connector 1a and a plug-type connector 22 for inserting into the connector 2a on the optical terminal board 2 side are provided. Further, the optical signal detector 20 includes a terminal 23 for connecting the connector 61 of the connection cable 60, a photodetection circuit for branching the optical signal and outputting an electric signal corresponding to the intensity. The connectors 21 and 22, the terminal 23, the light detection circuit, and the like are integrally configured by a housing 24.
[0038]
On the other hand, the optical signal indicator 40 is a portable measuring instrument that displays the state of the optical signal in the optical transmission path based on the electrical signal output from the terminal 23 of the optical signal detector 20. On the front panel of the optical signal display 40, switches (SW) 41, 42, 43, 44 for setting measurement conditions and the like, and LEDs 45, 46a, which are display units for displaying setting states, signal states, etc. 46b, 47, 48a, 48b, a 7 segment type display unit 49 for displaying the measurement result numerically, and the like are arranged. In addition, the case of the optical signal display 40 is provided with a connector 50 for connecting the connector 62 on the connection cable 60 side, and a measurement circuit including a microcomputer is accommodated in the case as will be described later. Has been.
[0039]
FIG. 3 is a cross-sectional view of the optical signal detector in FIG.
[0040]
The optical signal detector 20 has connectors 21, 22 and the like integrated into a housing 24. The housing 24 is a robust and light-shielding case precisely formed of engineering plastic or the like. A through hole 24X for arranging an optical transmission path is provided in the center of the housing 24, and both sides of the through hole 24X are provided. Connectors 21 and 22 are formed. In addition, the housing 24 is provided with an internal space 24Y in which a light detection circuit such as a light receiving element is disposed in order to detect light branched in the optical transmission path.
[0041]
A sleeve 25 having an outer diameter substantially equal to the inner diameter of the through hole 24X is housed inside the through hole 24X. For example, the sleeve 25 is formed by forming a metal plate of about 0.5 mm in a cylindrical shape, and the diameter can be finely adjusted by an axial slit. At positions corresponding to the inner space 24Y of the housing 24 at the center portion of the sleeve 25, through holes 25a and 25b for guiding a part of the optical signal to the inner space 24Y are provided.
[0042]
Optical fibers 27a and 27b protected by ferrules 26a and 26b are inserted into the sleeve 25 from both ends thereof. The ferrules 26a and 26b are tubular members made of a light-transmitting material such as glass for reinforcing the optical fibers 27a and 27b and accurately aligning them. The optical fibers 27a and 27b are respectively inserted into the ferrules 26a and 26b and fixed with an adhesive or the like, and then, together with the ferrules 26a and 26b, the branch surfaces thereof have a predetermined angle (for example, 45 °). Polished. Further, the end faces of the optical fibers 27a and 27b on the side of the connectors 21 and 22 are polished together with the ferrules 26a and 26b so as to be accurately 90 °.
[0043]
The branch surfaces of the optical fibers 27 a and 27 b protected by the ferrules 26 a and 26 b are in surface contact so that no gap is generated at the center portion of the sleeve 25 with the branch film 28 as a branch portion interposed therebetween. The branch film 28 is formed by depositing a metal film on a polyimide film, for example, and allows most of the optical signals to pass therethrough and specularly reflects some of the optical signals.
[0044]
Circuit boards 29 a and 29 b are fixed to the side surface of the housing 24. Inside the circuit board 29a, a terminal 23 for connecting the connection cable 60, and a light detection circuit such as a PD 30a serving as a detection unit and an LED 31a serving as a light emission unit are mounted. Further, inside the circuit board 29b, photodetection circuits such as a PD 30b and an LED 31b are mounted.
[0045]
The PD 30a detects an optical signal reflected by the branch film 28 among optical signals transmitted from the optical fiber 27a side to the optical fiber 27b side. The PD 30b detects an optical signal reflected by the branch film 28 among optical signals transmitted from the optical fiber 27b side to the optical fiber 27a side. Further, the LEDs 31a and 31b provide test light to the PDs 30a and 30b, respectively, for checking the detection function.
[0046]
FIG. 4 is a block diagram showing an example of the circuit configuration of FIG.
[0047]
The optical signal detector 20 includes a PD 30a for detecting a part of an optical signal incident from the optical fiber 1, and an LED 31a for supplying test light to the PD 30a. The optical signal detector 20 includes a PD 30b for detecting a part of the optical signal incident from the optical terminal board 2, and an LED 31b for supplying test light to the PD 30b. Amplifiers 32a and 32b for amplifying signals output from the PDs 30a and 30b to a predetermined level are connected to the output sides of the PDs 30a and 30b, respectively. The output signals of the amplifiers 32a and 32b are output from the terminal 23. A test signal for driving the PDs 31 a and 31 b and power supply voltages + VCC and −VCC for the amplifiers 32 a and 32 b are supplied from a terminal 23.
[0048]
On the other hand, the optical signal indicator 40 has a power source unit 51 such as a battery, and a power source necessary for the optical signal detector 20 and the optical signal indicator 40 from the power source unit 51 via the power switch 41. Voltages + VCC and -VCC are supplied. The power supply voltage + VCC is supplied to the LED 45 for power supply display, and is output as a test signal for the LEDs 31a and 31b of the optical signal detector 20 via the test switch 44 which is a test unit.
[0049]
The optical signal indicator 40 includes a microcomputer including an input port 52, a CPU (central processing unit) 53 that is a determination unit, an output port 54, and the like. Optical signals detected by the PDs 30a and 30b of the signal detector 20 are given. The input port 52 includes an A / D converter, and an electrical signal supplied from the optical signal detector 20 is converted into digital data corresponding to the intensity of the optical signal and supplied to the CPU 53.
[0050]
Furthermore, the input port 52 is connected to a measurement switch 42 for instructing start / end of measurement, a selection switch 43 for selecting the wavelength of the optical signal to be measured (for example, 1.31 μm or 1.55 μm), and the like. Measurement conditions specified by these switches 42 and 43 are given to the CPU 53.
[0051]
Further, an output port 54 is connected to the CPU 53, and status display LEDs 46 to 48 and a display unit 49 for numerically displaying the optical signal level of the measurement result are driven via the output port 54. Yes.
[0052]
Next, the operation will be described.
[0053]
For example, it is assumed that an optical signal is propagated from the optical fiber 1 toward the optical terminal board 2. At this time, a part of the propagated optical signal is branched by the branch film 28 of the optical signal detector 20, passes through the through hole 25a, and enters the PD 30a. Thus, incident light is detected by the PD 30a, and a voltage corresponding to the intensity of the incident light is output and applied to the amplifier 32a. The electrical signal amplified to a predetermined level by the amplifier 32a is output from the terminal 23 to the optical signal display 40 via the connection cable 60.
[0054]
The electric signal given to the optical signal indicator 40 is converted into light intensity by a digital value at the input port 52 and held.
[0055]
At the same time, the optical signal is also detected by the PD 30b. However, since almost no light is output through the through hole 25b at this time, the intensity of the light detected by the PD 30b is very weak and the output voltage is extremely small. Therefore, an extremely small voltage is input to the input port 52, and the light intensity based on the digital value is maintained.
[0056]
Next, the two light intensities corresponding to the PDs 30a and 30b held in the input port 52 are read out and compared by the CPU 53. When the difference between the two light intensities exceeds the reference value, the LED 46 a indicating the direction of the optical signal is turned on from the CPU 53 via the output port 54. Further, the intensity of light detected by the PD 30 a is displayed as a numerical value on the display unit 49 from the CPU 53 via the output port 54.
[0057]
When an optical signal is propagated from the optical terminal board 2 toward the optical fiber 1, a large voltage is generated in the PD 30b, and an extremely small voltage is generated in the PD 30a. As a result, the LED 46b is turned on by the determination of the CPU 53, and the intensity of light detected by the PD 30b is displayed as a numerical value on the display unit 49.
[0058]
The wavelength of the optical signal propagating through the optical transmission line is 1.31 μm or 1.55 μm, and the wavelength is selected by the selection switch 43. A signal from the selection switch 43 is read by the CPU 53 via the input port 52. As a result, the CPU 53 corrects the intensity of the optical signal in accordance with the selected wavelength and displays it on the display unit 49 as a numerical value.
[0059]
Further, by operating the test switch 44 of the optical signal indicator 40, the LEDs 31a and 31b in the optical signal detector 20 can be selected and turned on. For example, the LED 31a is turned on by tilting the test switch 44 to the A side, and the light enters the PD 30a. As a result, the LED 46 a of the optical signal display 40 is turned on, and the intensity of the propagation light assumed at that time is displayed on the display unit 49.
[0060]
As described above, the optical signal monitoring apparatus according to the first embodiment has the following advantages.
[0061]
(1) Since the optical signal detector 20 and the optical signal indicator 40 are separated, the optical signal detector 20 inserted into the optical transmission path can be downsized. The optical signal detector 20 includes a receptacle-type connector 21 that can be connected to the connector 1a on the optical fiber 1 side as it is, and a plug-type connector 22 for connecting the connector 2a on the optical terminal board 2 side as it is. Yes. Thereby, it can mount | wear with the optical terminal board 2 in which the connector 2a was mounted in high density as it is as an adapter.
[0062]
(2) In the optical signal detector 20 required for each optical transmission line, the function of judging and displaying the intensity of the optical signal while suppressing the minimum function such as light detection is an optical signal display that can be used in common. It is designed to be held on the 40 side. For this reason, the cost of the optical signal detector 20 can be reduced, and the cost of the entire equipment can be suppressed.
[0063]
(3) The optical signal indicator 40 has an input port 52, a CPU 53, and the like for converting the intensity of the optical signal detected by the optical signal detector 20 into a digital value and processing it. Thereby, the direction and intensity | strength of an optical signal can be measured accurately and reliably.
[0064]
(4) Since the optical signal display 40 is portable and small, it is easy to carry and improves workability and convenience during maintenance.
[0065]
(Second Embodiment)
[0066]
FIG. 5 is a block diagram of an optical signal monitoring apparatus showing a second embodiment of the present invention. Elements common to those in FIG. 1 are denoted by common reference numerals.
[0067]
This optical signal monitoring device is inserted between the optical fiber 1 and the optical terminal board 2 and monitors the direction and intensity of the optical signal transmitted in the optical transmission line. It comprises a detector 80 and an optical signal display 40A.
[0068]
The optical branching device 70 branches a part of the optical signal transmitted to the optical transmission line, and includes a receptacle-type connector 71 for inserting the connector 1a on the optical fiber 1 side, and a connector on the optical terminal board 2 side. It has a plug-type connector 72 for inserting into 2a. The optical branching unit 70 has through holes 73a and 73b for outputting the branched optical signal to the outside.
[0069]
The optical signal detector 80 detects the optical signal branched and output by the optical splitter 70 and outputs an electrical signal corresponding to the intensity of the detected optical signal. , 73b from the outside, a U-shaped member 81 is formed. Inside the U-shaped member 81, PDs 82 a and 82 b are provided that receive optical signals output from the through holes 73 a and 73 b of the optical branching device 70 and convert them into electrical signals according to their strengths. The optical signal detector 80 is connected to the optical signal indicator 40A by a cable 84 and a connector 85.
[0070]
The optical signal indicator 40A displays the state of the optical signal in the optical transmission line based on the electrical signal output from the optical signal detector 80. On the front panel of the optical signal indicator 40A, switches 41, 43, 55 for setting power on / off, measurement conditions, etc., and LEDs 46a, 46b, 47, 48a which are display units for displaying the status and the like. , 48b, 57, and a 7-segment display 49 for displaying the measurement results numerically. The case of the optical signal indicator 40A is provided with a connector 50 for connecting a connector 85 on the optical signal detector 80 side, and a DC jack 58 for receiving DC power from an AC adapter or the like. Further, a measurement circuit including a microcomputer is accommodated in the case of the optical signal display 40A, as will be described later.
[0071]
FIG. 6 is a cross-sectional view of the optical branching device in FIG.
[0072]
This optical branching device 70 has connectors 71, 72, etc. integrated into a housing 73. The housing 73 is a robust light-shielding case precisely formed of engineering plastic or the like, and a through hole 73X for arranging an optical transmission path is provided in the center of the housing 73, and both sides of the through hole 73X are provided. Connectors 71 and 72 are formed. The housing 73 is provided with through holes 73a and 73b for outputting a part of the optical signal branched in the optical transmission path to the outside.
[0073]
A sleeve 74 having an outer diameter substantially equal to the inner diameter of the through hole 73X is housed inside the through hole 73X. The sleeve 74 is formed by, for example, forming a metal plate of about 0.5 mm in a cylindrical shape, and the diameter can be finely adjusted by an axial slit. At positions corresponding to the through holes 73a and 73b of the housing 73 at the center of the sleeve 74, through holes 74a and 74b for guiding a part of the optical signal to the through holes 73a and 73b are provided.
[0074]
Optical fibers 76a and 76b protected by ferrules 75a and 75b are inserted into the sleeve 74 from both ends thereof. The ferrules 75a and 75b are tubular members formed of a light-transmitting material such as glass for reinforcing the optical fibers 76a and 76b and accurately aligning the optical fibers 76a and 76b, respectively. The optical fibers 76a and 76b are inserted into the ferrules 75a and 75b and fixed with an adhesive or the like, respectively, and then, along with the ferrules 75a and 75b, the branch surfaces thereof have a predetermined angle (for example, 45 °). Polished. Further, the end faces of the optical fibers 76a and 76b on the connectors 71 and 72 side are polished together with the ferrules 75a and 75b so as to be accurately 90 °.
[0075]
The branch surfaces of the optical fibers 76a and 76b protected by the ferrules 75a and 75b are in surface contact so that a gap is not generated between the branch film 77 as a branch portion at the center of the sleeve 74. The branch film 77 is formed, for example, by depositing a metal film on a polyimide film, and allows most of the optical signals to pass therethrough and specularly reflects some of the optical signals. As a result, a part of the optical signal incident from the connector 71 on the optical fiber 1 side is reflected by the branch film 77, passes through the through holes 74 a and 73 a, and is output to the outside, and the connector 72 on the optical terminal board 2 side. A portion of the optical signal incident from is reflected by the branch film 77, passes through the through holes 74b and 73b, and is output to the outside.
[0076]
FIG. 7 is a block diagram showing an example of the circuit configuration of FIG.
[0077]
The optical signal detector 80 detects the optical signal input from the optical terminal board 2 and the PD 82a for detecting the optical signal input from the optical fiber 1 side and output from the through hole 73a of the optical splitter 70. PD82b for this purpose. Amplifiers 83a and 83b for amplifying electrical signals output from the PDs 82a and 82b to a predetermined level are connected to the output sides of the PDs 82a and 82b, respectively.
[0078]
The output signals of the amplifiers 83a and 83b are given from the connector 85 to the optical signal indicator 40A via the cable 84. The power supply voltages + VCC and -VCC for driving the PDs 82a and 82b and the amplifiers 83a and 83b are supplied from the optical signal display 40A side through the connector 85.
[0079]
The optical signal indicator 40A has a power supply unit 51 such as a battery, and the power supply voltage + VCC, VCC required in the optical signal detector 80 and the optical signal display unit 40A via the switch 41 from the power supply unit 51. -VCC is supplied. The power supply voltage + VCC is supplied to the LED 47 for measurement display and is also supplied to the low voltage detection unit 56.
[0080]
The low voltage detector 56 turns on the LED 57 and displays a LOW-BATT warning when the power supply voltage + VCC drops below a certain voltage. Further, the optical signal indicator 40A has a DC jack 58 connected to the power supply voltages + VCC and -VCC, and the power supply voltages + VCC and -VCC are supplied from an external AC adapter or the like via the DC jack 58. It can be supplied.
[0081]
The optical signal indicator 40A includes a microcomputer including an input port 52, a CPU 53 as a determination unit, an output port 54, and the like. The input port 52 includes a PD 82a of the optical signal detector 80. , 82b and a signal converted into an electric signal is provided. The input port 52 includes an A / D conversion unit, and an electric signal supplied from the optical signal detector 80 is converted into digital data corresponding to the intensity of the optical signal and supplied to the CPU 53.
[0082]
Further, the input port 52 is connected to switches 43 and 55 for selecting the wavelength (for example, 1.31 μm or 1.55 μm) of the optical signal to be measured and the HIGH and LOW light reception levels. , 55, etc., are given to the CPU 53.
[0083]
Further, an output port 54 is connected to the CPU 53, and status display LEDs 46a, 46b, 48a, 48b, and a display unit 49 for numerically displaying the level of the optical signal of the measurement result are driven through the output port 54. It is like that.
[0084]
Next, the operation will be described.
[0085]
Prior to monitoring, the optical branching device 70 is inserted between the connector 1a of the optical fiber 1 to be monitored for the optical signal and the connector 2a of the optical terminal board 2 corresponding thereto. Further, the U-shaped member 81 of the optical signal detector 80 is sandwiched so that the PDs 82a and 82b of the optical signal detector 80 face the through holes 73a and 73b of the optical splitter 70, respectively. Further, the connector 85 of the optical signal detector 80 is connected to the connector 50 of the optical signal indicator 40A. After the above preparation is completed, the switch 41 of the optical signal indicator 40A is turned on.
[0086]
For example, when an optical signal is propagated from the optical fiber 1 toward the optical terminal board 2, a part of the propagated optical signal is branched by the branch film 77 of the optical branching device 70, and the through holes 74a and 73a. And enter the PD 82a of the optical signal detector 80. Thus, incident light is detected by the PD 82a, and a voltage corresponding to the intensity of the incident light is output and applied to the amplifier 83a.
[0087]
The electrical signal amplified to a predetermined level by the amplifier 83a is output to the optical signal indicator 40A via the cable 84. The electrical signal given to the optical signal indicator 40A is converted into a digital light intensity at the input port 52 and held.
[0088]
At the same time, an optical signal is detected by the PD 82b of the optical signal detector 80. However, at this time, since almost no light is output through the through holes 74b and 73b of the optical branching device 70, the intensity of the light detected by the PD 82b is very weak and the output voltage is extremely small. Therefore, an extremely small voltage is input to the input port 52, and the light intensity based on the digital value is maintained.
[0089]
Next, the two light intensities corresponding to the PDs 82a and 82b held in the input port 52 are read out and compared by the CPU 53. When the difference in intensity between the two lights exceeds the reference value, the LED 46 a indicating the direction of the optical signal is turned on from the CPU 53 via the output port 54. Further, the intensity of light detected by the PD 82 a is displayed numerically on the display unit 49 from the CPU 53 via the output port 54.
[0090]
When an optical signal is propagated from the optical terminal board 2 toward the optical fiber 1, a large voltage is generated in the PD 82b, and an extremely small voltage is generated in the PD 82a. As a result, according to the determination of the CPU 53, the LED 46b is turned on, and the light intensity detected by the PD 82b is displayed as a numerical value on the display unit 49.
[0091]
Since there are 1.31 μm and 1.55 μm types of wavelengths of the optical signal propagating through the optical transmission line, the wavelength is selected by the selection switch 43. A signal from the selection switch 43 is read by the CPU 53 via the input port 52. As a result, the CPU 53 corrects the intensity of the optical signal in accordance with the selected wavelength and displays it on the display unit 49 as a numerical value.
[0092]
Further, the light receiving level can be switched between HIGH and LOW by the switch 55 of the optical signal indicator 40A. As a result, the level of the input signal to the A / D converter in the input port 52 is switched, and the intensity of the optical signal can be read with high accuracy.
[0093]
For example, when the switch 55 is set to HIGH, the measurement range is −45 to −15 dBm, and the numerical value is displayed on the display unit 49 if the intensity of the optical signal is within this range. When the intensity of the optical signal is −14 dBm or more, “HH” is displayed on the display unit 49, and when it is −46 dBm or less, “-” is displayed and the LED 48a is turned on. When the switch 55 is set to LOW, the measurement range is −25 to 6 dBm, and the numerical value is displayed on the display unit 49 if the intensity of the optical signal is within this range. When the intensity of the optical signal is −26 dBm or less, “LL” is displayed on the display unit 49, and when it is 7 dBm or more, “−−” is displayed and the LED 48b is turned on.
[0094]
As described above, the optical signal monitoring apparatus according to the second embodiment has the following advantages in addition to the advantages (3) and (4).
[0095]
(5) Since the optical splitter 70, the optical signal detector 80, and the optical signal indicator 40A are separated, the optical splitter 70 inserted into the optical transmission path can be further reduced in size. The optical branching device 70 has a receptacle-type connector 71 that can be connected to the connector 1a on the optical fiber 1 side as it is, and a plug-type connector 72 for connecting the connector 2a on the optical terminal board 2 side as it is. . Thereby, it can mount | wear with the optical terminal board 2 in which the connector 2a was mounted in high density as it is as an adapter.
[0096]
(6) The optical branching unit 70 required for each optical transmission line is limited to the function of only branching the monitoring light, and the function of converting the optical signal into an electric signal, determining the signal intensity, and displaying The optical signal detector 80 and the optical signal display 40A that can be used in common are provided on the side. Thereby, the cost of the optical branching device 70 can be reduced, and the cost of the entire equipment can be further suppressed.
[0097]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. Examples of this modification include the following.
[0098]
(A) The shapes of the connectors 21 and 22 of the optical signal detector 20 and the connectors 71 and 72 of the optical branching device 70 are not limited to those illustrated. It is necessary to use one corresponding to the connector 2a of the optical terminal board 2 that is actually applied.
[0099]
(B) The structures of the housing 24 of the optical signal detector 20 and the housing 73 of the optical branching device 70 are not limited to those illustrated.
[0100]
(C) The illustrated optical signal display 40 includes the connector 50 for connecting the connector 62 of the connection cable 60, but the connection cable 60 is fixedly connected to the optical signal display 40 without using the connector. You may make it do. Thereby, the cost can be reduced.
[0101]
(D) The types and arrangement of switches, LEDs, and the like on the panels in the optical signal indicators 40, 40A are not limited to those illustrated. More functions can be added as needed.
[0102]
(E) The optical signal detector 20 is provided with amplifiers 32a and 32b for amplifying the output signals of the PDs 30a and 30b. When the output signals of these PDs 30a and 30b are larger than noise or the like, These amplifiers 32a and 32b are not necessary. By eliminating the amplifiers 32a and 32b, it is not necessary to supply the power supply voltages + VCC and -VCC, and the optical signal detector 20 can be further reduced in size and cost. The same applies to the amplifiers 83a and 83b for the PDs 82a and 82b in the optical signal detector 80.
[0103]
(F) The circuit configuration of the optical signal indicators 40 and 40A is not limited to the illustrated one. For example, a liquid crystal display or the like may be used instead of the LED 46, the display unit 49, or the like. Thereby, power consumption can be reduced.
[0104]
【The invention's effect】
[0105]
  As described in detail above, according to the first invention, the optical signal monitoring device is inserted into the optical transmission line to detect the optical signal, and the optical signal detector outputs the optical signal detector. It consists of an optical signal indicator that displays the status of optical signals based on electrical signals.The
[0106]
  And thisIn addition to the two connectors for connecting between the optical fiber of the optical transmission line and the connector of the optical terminal board, the optical signal detector, in addition to the branching unit and the detecting unit for branching and detecting bidirectional optical signals, A light emitting unit for outputting test light is provided. The optical signal display is connected to the optical signal detector with a cable, and an A / D conversion unit, a determination unit, a display unit, and a test unit for determining and displaying the propagation direction and intensity of the optical signal Etc. Thereby, the direction and intensity | strength of an optical signal can be measured accurately and reliably.
[0107]
  First2According to the invention, the optical signal monitoring device inserts the optical signal monitoring device into the optical transmission line and branches the optical signal, and the light that detects the optical signal branched by the optical branching device and converts it into an electrical signal. It consists of a signal detector and an optical signal indicator that displays the state of the optical signal based on the electrical signal output from this optical signal detector.The
[0108]
  And thisThe optical branching device includes two connectors for connecting between the optical fiber of the optical transmission line and the connector of the optical terminal board, and two through holes for outputting optical signals according to branched directions. The optical signal detector includes a detection unit that converts the optical signal output from the optical branching device into an electrical signal. In addition, the optical signal display has an A / D conversion unit, a determination unit, and a display unit for determining and displaying the propagation direction and intensity of the optical signal. Thereby, the direction and intensity | strength of an optical signal can be measured accurately and reliably.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical signal monitoring apparatus according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a conventional photodetection device.
3 is a cross-sectional view of the optical signal detector in FIG. 1. FIG.
4 is a block diagram showing an example of the circuit configuration of FIG. 1. FIG.
FIG. 5 is a configuration diagram of an optical signal monitoring apparatus showing a second embodiment of the present invention.
6 is a cross-sectional view of the optical branching device in FIG. 5. FIG.
7 is a block diagram showing an example of the circuit configuration of FIG. 5. FIG.
[Explanation of symbols]
1, 27a, 27b Optical fiber
1a, 2a, 21, 22, 71, 72 connectors
2 Optical terminal board
20, 80 Optical signal detector
23 terminals
24 Housing
28,77 Branched membrane
30a, 30b PD (photodiode)
31a, 31b LED (light emitting diode)
40, 40A optical signal indicator
44 Test switch
49 Display
52 Input port
53 CPU (Central Processing Unit)
54 output ports
60 Connection cable
70 Optical splitter
73a, 73b Through hole

Claims (2)

An optical signal detector that is inserted into an optical transmission line, detects a part of an optical signal transmitted through the optical transmission line by branching, and outputs an electrical signal corresponding to the intensity of the detected optical signal from a terminal. And an optical signal display for displaying the state of the optical signal in the optical transmission line based on an electrical signal output from the optical signal detector, connected to a terminal of the optical signal detector via a connection cable In the optical signal monitoring device composed of
The optical signal detector is:
A receptacle-type first connector for connecting a plug-type connector on the optical fiber side in the optical transmission line;
A plug-type second connector for connecting to a receptacle-type connector on the optical terminal board side in the optical transmission line;
The optical signal propagating through the optical fiber connecting the first and second connectors is provided at a predetermined angle with respect to the optical axis of the optical signal to pass through most of the optical signal. And a branch part for specular reflection of a part thereof,
A first detection unit that detects an optical signal propagated from the first connector to the branch unit and regularly reflected by the branch unit, and outputs an electrical signal corresponding to the intensity of the detected optical signal;
A second detection unit that detects an optical signal that is propagated from the second connector to the branching unit and is regularly reflected by the branching unit, and that outputs an electrical signal corresponding to the intensity of the detected optical signal;
First and second light emitting units for directly supplying test light to the first and second detection units, respectively;
A terminal for inputting / outputting an electric signal output from the first and second detection units and an electric signal for driving the first and second light emitting units;
A housing for integrating the first and second connectors, the terminals, the branching portion, the first and second detection portions, and the first and second light emitting portions;
The optical signal indicator is
An analog-to-digital converter that converts the electrical signals supplied from the first and second detectors into digital values;
A discriminating unit for discriminating a propagation direction of an optical signal propagating through the optical fiber based on the intensity of the light converted into a digital value by the analog / digital converting unit;
A display unit that displays the propagation direction determined by the determination unit and the intensity of light in the propagation direction;
A test unit that drives the first and second light emitting units of the optical signal detector during the test,
An optical signal monitoring device. An optical branching device that is inserted into the optical transmission line and branches and outputs a part of the optical signal transmitted to the optical transmission line, and a part of the optical signal output from the optical branching unit is detected. An optical signal detector that outputs an electrical signal corresponding to the intensity of the detected optical signal, and light that displays the state of the optical signal in the optical transmission path based on the electrical signal output from the optical signal detector In an optical signal monitoring device composed of a signal indicator,
The optical splitter is
A receptacle-type first connector for connecting a plug-type connector on the optical fiber side in the optical transmission line;
A plug-type second connector for connecting to a receptacle-type connector on the optical terminal board side in the optical transmission line;
The optical signal propagating through the optical fiber connecting the first and second connectors is provided at a predetermined angle with respect to the optical axis of the optical signal to pass through most of the optical signal. And a branch part for specular reflection of a part thereof,
A first through hole that outputs the optical signal propagated from the first connector to the branch portion and specularly reflected to the outside, and an optical signal propagated from the second connector to the branch portion and specularly reflected. And a housing having a second through hole that outputs to the outside,
The optical signal detector is:
An optical signal output from the first through hole of the optical branching unit is detected, and according to the intensity of the optical signal A first detector for outputting an electrical signal;
A second detection unit that detects an optical signal output from the second through hole of the optical splitter and outputs an electrical signal according to the intensity of the optical signal;
The optical signal indicator is
An analog-to-digital converter that converts the electrical signals supplied from the first and second detectors into digital values;
A discriminating unit for discriminating a propagation direction of an optical signal propagating through the optical fiber based on the intensity of the light converted into a digital value by the analog / digital converting unit;
An optical signal monitoring apparatus comprising: a propagation direction discriminated by the discrimination unit; and a display unit that displays the intensity of light in the propagation direction.

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