JPH05322697A - Portable optical circuit checker - Google Patents

Abstract

PURPOSE:To obtain an accurate, simple, and rapid portable optical circuit checker with a high S/N ratio and a wide dynamic range which can indirectly and visually confirm presence or absence of disconnection of an optical circuit which is constituted of a waveguide path such as an optical fiber by including an optical noise generation source such as an optical fiber amplifier halfway. CONSTITUTION:The outer terminal of optical connectors 9 and 10 which are adhered to the side wall of a portable equipment enclosure beta is formed to be connected and removed easily at one touch by a transmission/reception terminal. Then, an photoelectric conversion part alpha 1 with a signal light source 1 which is modulated directly or indirectly by a certain frequency F and a means 5 for extracting electrical signal strength of a frequency is connected to the inner terminal of the optical connectors 9 and 10 and is incorporated in the equipment enclosure beta, thus detecting presence or absence of disconnection of an optical circuit 3 to be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable optical circuit checker for checking the presence / absence of disconnection of an optical circuit by a simple method.

[0002]

2. Description of the Related Art The use of optical communication systems using optical waveguides such as optical fibers is progressing from backbone transmission lines to homes, and in addition, complicated configurations such as branching and merging of optical signals are common. It is becoming more common. Further, in order to compensate the loss due to branching and merging, use of an optical fiber amplifier or the like is considered, but the optical amplifier also has a property as an optical noise generation source. In the conventional optical communication system with a simple configuration, it was possible to easily visually check for the presence or absence of an optical circuit disconnection, but in the future complicated subscriber systems, etc., it is impossible to directly confirm the presence or absence of an optical circuit disconnection. Conceivable.

[0003]

As an alternative to the direct visual confirmation, a method of actually inputting an optical signal into an optical circuit to be measured and confirming the signal light intensity with an optical power meter is conceivable. In an optical circuit in which an optical noise generation source such as the above is interposed midway, the input optical signal is buried in the noise and cannot be confirmed by the optical power meter.

A method of confirming the presence of signal light by measuring an optical signal spectrum using an optical spectrum analyzer may be considered. However, when the optical noise from the optical noise source is large, the With a spectrum analyzer, a sufficient S / N ratio cannot be secured, so confirmation becomes impossible.

According to the present invention, the presence / absence of a disconnection of an optical circuit which connects an optical noise source in the middle can be confirmed directly except by visual observation, which is accurate, simple, quick, has a high S / N ratio, and is dynamic. It aims to provide a portable optical circuit checker with a wide range.

[0006]

The solution to the above-mentioned problems can be achieved by adopting the novel characteristic construction means enumerated below by the present invention. That is, the first feature of the present invention is that an oscillator, a signal light source modulated by the oscillator, a first optical connector for connecting the output of the signal light source to a measurement optical circuit, and a return from the measurement optical circuit. A second optical connector for receiving the output of the signal light source, and an electric signal strength of the oscillation frequency of the oscillator extracted from the return light passing through the second optical connector to determine whether or not the measurement optical circuit is disconnected. Light to detect
A portable type having an electrical conversion unit, the oscillator, the signal light source, the optical-electrical conversion unit, and a housing in which the first optical connector and the second optical connector are attached to one side. Optical circuit checker.

A second aspect of the present invention is a portable optical circuit checker in which the opto-electrical conversion section in the first aspect comprises a light receiving element, an electric signal band pass filter, and an electric signal strength detector. Is.

A third aspect of the present invention is a portable optical circuit checker in which the optical-electrical conversion section in the first aspect is constituted by a light receiving element, a bandpass filter for an electric signal and an oscilloscope.

A fourth aspect of the present invention is a portable optical circuit checker in which the optical-electrical conversion section in the first aspect is composed of a light receiving element and a spectrum analyzer of electric signals.

[0010]

According to the present invention, by taking the above-mentioned means, the signal light source is directly or indirectly modulated at a certain frequency, the signal light output at the optical circuit output is converted into an electric signal, and the frequency signal is outputted. The presence or absence of the optical circuit disconnection is determined by electrically detecting the component.

In the first place, when comparing an optical signal and an electric signal, it is easy to construct a bandpass filter having a very narrow band with the electric signal, so that the electric signal has a higher S / N ratio. be able to. Therefore, it is possible to detect an optical signal that is buried in optical noise and cannot be detected by ordinary means (such as the use of an optical power meter) in the form of being converted into an electrical signal with a high S / N ratio, and thus is buried in noise. It is possible to accurately detect an optical signal that has been lost.

[0012]

First Embodiment A first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a see-through internal circuit of this embodiment to which an optical circuit under test is connected. In the figure, A is a portable optical circuit checker of the present embodiment, 1 is a signal light source, 2 is an oscillator having an oscillation frequency F of, for example, 4 MHz, 3 is an optical circuit to be measured, 4 is a light receiving element, 5 is a light receiving element. It is a band-pass filter for electric signals in the 4 MHz band.

Reference numeral 6 is an electric signal strength detector, 7 is an optical fiber, 8 is an electric wire, and 9 and 10 are the one-touch connection and disconnection of the optical circuit 3 to be measured and the portable optical circuit checker A of this embodiment. , Α1 is an optical-electrical conversion unit composed of the light receiving element 4, the bandpass filter 5 and the electric signal strength detector 6, and β is a portable device. The measured optical circuit 3 includes a group of optical amplifiers 3a which are sources of optical noise.

The specification of this embodiment is such a concrete embodiment, and its operation will be described below. First, the optical signal L1 modulated by the oscillation frequency F of the oscillator 2 is sent out from the transmitting optical connector 9 to the measured optical circuit 3 and further input from the receiving optical connector 10 to the measured optical circuit 3. If there is no disconnection, the light receiving element 4 receives the light signal L2. At this time, the power Po of the optical signal L2 is received by the light receiving element 4.
Is converted into the power Pe of the electric signal S1. However, the power Pe of the electric signal S1 is affected by the optical noise generated by the optical amplifier 3a which is a noise source built in the measured optical circuit 3, and the power Pe of the electric signal S2 is It is not proportional to the power Po.

However, the power Pe of this electric signal S1
Passes through the bandpass filter 5 corresponding to the oscillation frequency F of the oscillator 2 so that only the component proportional to the power Po of the optical signal L2 is extracted and detected by the electric signal intensity detector 6. Since the Q value of the band pass filter 5 can be easily made very high, the S value is higher than that of the optical signal L2.
It is possible to detect a signal strength with a high / N ratio. Therefore, it is possible to easily determine whether or not the optical circuit 3 to be measured has a disconnection depending on whether or not the signal component is detected.

The oscillation frequency F of the oscillator 2 can be arbitrarily set as long as it is higher than the reduction cutoff frequency of the optical amplifier 3a in the optical circuit 3 to be measured. From the viewpoints of economy of 5 and the like, easiness of increasing the Q value of the bandpass filter 5, and the like, it is not desirable that the frequency is very high, so that it is considered that 1 kHz or more and several 100 MHz or less are practical. ..

(Second Embodiment) A second embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a see-through internal circuit of this embodiment to which an optical circuit to be measured is connected. In the figure, B is the portable optical circuit checker of this embodiment, 1 is a signal light source, and 2 is, for example, 4
An oscillator having an oscillation frequency F of MHz, 3 is a measured optical circuit to be measured, 4 is a light receiving element, and 5 is a band-pass filter for an electric signal in the 4 MHz band.

Reference numeral 7 is an optical fiber, 8 is an electric wire, and 9 and 10 are light for transmission and reception for connecting the optical circuit under test 3 and the portable optical circuit checker B of this embodiment in a one-touch connection and detachable manner. A connector, 11 is an oscilloscope, α2 is an optical-electrical conversion unit composed of the light receiving element 4, the bandpass filter 5 and the oscilloscope 11, and β is a portable device. Although not shown in FIG. 2, it goes without saying that the circuit under test 3 includes a group of optical amplifiers 3a, which are sources of optical noise, as in the first embodiment.

The specification of this embodiment is such a concrete embodiment, and its operation will be described below. First, the optical signal L1 modulated by the oscillation frequency F of the oscillator 2 passes from the optical connector 9 for transmission, the optical circuit 3 for measurement, and the optical connector 10 for reception, and there is no circuit disconnection in the optical circuit 3 for measurement. For example, the light receiving element 4 receives the light as the optical signal L2.

At this time, the power Po of the optical signal L2 is converted into the power Pe of the electric signal S1 by the light receiving element 4, but the optical noise generated by the noise source of the optical amplifier (not shown) built in the optical circuit 3 to be measured is generated. The power Pe of the electric signal S1 is not proportional to the power Po of the optical signal L2. However, the power Pe of the electric signal S1 passes through the bandpass filter 5 corresponding to the oscillation frequency F of the oscillator 2, so that only the component proportional to the power Po of the optical signal L2 is extracted and displayed on the screen of the oscilloscope 11. It

Therefore, if there is no break in the optical circuit 3 to be measured, the oscilloscope 11 causes the oscillator 2 to generate the oscillation frequency F.
The low frequency sine wave signal waveform corresponding to is detected and displayed on the screen. Therefore, it is possible to easily determine whether or not there is a break in the measured optical circuit 3 depending on whether or not the sine wave signal waveform is displayed on the screen of the oscilloscope 11.

The oscillation frequency of the oscillator 2 is set to the optical circuit 3
The frequency can be arbitrarily set as long as it is higher than the reduced cutoff frequency of the optical amplifier group in the inside, but it is considered that 1 kHz or more and several 100 MHz or less are practical as in the first embodiment.

(Third Embodiment) A third embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a see-through internal circuit of this embodiment to which an optical circuit to be measured is connected. In the figure, C is the portable optical circuit checker of this embodiment, 1 is a signal light source, and 2 is, for example, 4
Oscillator having an oscillation frequency F of MHz, 3 is an optical circuit to be measured as a measurement target, 4 is a light receiving element, 7 is an optical fiber, 8
Is an electric wire.

Numerals 9 and 10 are optical connectors for transmission and reception, respectively, for connecting the optical circuit 3 to be measured and the portable optical circuit checker C of this embodiment in a one-touch connection and detachment respectively, 12 is a spectrum analyzer, and α3 is α3. Light composed of the light receiving element 4 and the spectrum analyzer 12
The electrical conversion unit, β is a portable device housing. Although not shown in FIG. 3, it goes without saying that the optical circuit 3 to be measured includes an optical amplifier 3a group, which is an optical noise generation source, as in the first embodiment.

The specification of this embodiment is such a concrete embodiment, and its operation will be described below. First, the optical signal L1 modulated by the oscillation frequency F of the oscillator 2 passes from the optical connector 9 for transmission, the optical circuit 3 for measurement, and the optical connector 10 for reception, and there is no circuit disconnection in the optical circuit 3 for measurement. For example, the light receiving element 4 receives the light as the optical signal L2.

At this time, the power Po of the optical signal L2 is converted into the power Pe of the electric signal S1 by the light receiving element 4, but it is affected by the optical noise of an optical amplifier (not shown) generated by the optical circuit 3 to be measured, The power Pe of the electric signal S1 is the optical signal L2.
It is not proportional to the power Po of. However,
By inputting the power Pe of the electric signal S1 to the spectrum analyzer 12, only the spectrum corresponding to the oscillation frequency F of the oscillator 2 can be displayed on the spectrum analyzer 12.

Therefore, if there is no break in the optical circuit 3, the spectrum of the frequency of the low-frequency electric signal S1 corresponding to the oscillation frequency F of the oscillator 2 is observed on the screen of the spectrum analyzer 12. Whether or not the measured optical circuit 3 has a disconnection can be easily determined depending on whether or not the spectrum corresponding to the signal S1 is detected.

The oscillation frequency of the oscillator 2 is the same as the first frequency.
Similar to the embodiment or the second embodiment, any frequency can be set as long as it is higher than the reduced cutoff frequency of the optical amplifier in the optical circuit, but it is considered that 1 kHz or more and several 100 MHz or less are practical. Be done.

In the above-mentioned first to third embodiments, the signal light source 1 is directly modulated by the oscillator 2 but is not limited to this. Indirect modulation by other means is also within the technical idea of the present invention. Naturally included. Also, the optical connectors 9 and 1
0 may be attached to any of the upper, lower, left, right, front, and rear side walls of the portable device housing β.

[0030]

As described above, the present invention provides a simple and accurate method for verifying the presence or absence of circuit disconnection in a complicated optical circuit including an optical noise source by means other than direct visual inspection. With the spread of optical communication systems, optical circuits have become complicated, and disconnection due to human error or the like is likely to occur.

Therefore, it takes a lot of time and manpower to confirm the presence / absence of the disconnection, but the present invention greatly simplifies the confirmation work, and the confirmation work is also performed at the optical circuit facility site. It can be operated simply by connecting the transmitting and receiving ends of the optical circuit to the transmitting optical connector and the receiving optical connector by one-touch operation, and it is possible to perform indirect visual confirmation through various output indicators, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a perspective internal circuit showing a first embodiment of the present invention in which an optical circuit to be measured is connected.

FIG. 2 is a perspective internal circuit showing a second embodiment of the same.

FIG. 3 is a perspective internal circuit showing the third embodiment.

[Explanation of symbols]

 A, B, C ... Portable optical circuit checker F ... Oscillation frequency L1, L2 ... Optical signal S1 ... Electrical signal α1, α2, α3 ... Optical-electrical converter β ... Portable device case 1 ... Signal light source 2 ... Oscillator 3 ... Optical circuit under test 4 ... Light receiving element 5 ... Band pass filter 6 ... Electrical signal strength detector 7 ... Optical fiber 8 ... Electric wire 9 ... Optical connector for transmission 10 ... Optical connector for reception 11 ... Oscilloscope 12 ... Spectrum analyzer

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroharu Wakabayashi 2-3-2 Nishishinjuku, Shinjuku-ku, Tokyo International Telegraph and Telephone Corporation

Claims (4)

[Claims] 1. An oscillator, a signal light source modulated by the oscillator, a first optical connector for connecting an output of the signal light source to a measurement optical circuit, and a signal light source returned from the measurement optical circuit. A second optical connector that receives an output and an optical-electrical device that extracts the electrical signal strength of the oscillation frequency of the oscillator from the return light that has passed through the second optical connector and detects the presence or absence of a disconnection of the measurement optical circuit. It is possible to have a housing that houses the converter, the oscillator, the signal light source, and the opto-electric converter, and has the housing in which the first optical connector and the second optical connector are attached to one side. Portable optical circuit checker 2. The portable optical circuit checker according to claim 1, wherein the optical-electrical conversion unit is composed of a light receiving element, a bandpass filter for an electric signal, and an electric signal strength detector. 3. The portable optical circuit checker according to claim 1, wherein the optical-electrical conversion unit is composed of a light receiving element, a bandpass filter for electric signals, and an oscilloscope. 4. The portable optical circuit checker according to claim 1, wherein the optical-electrical conversion unit is composed of a light receiving element and a spectrum analyzer for electric signals.