WO2014183412A1

WO2014183412A1 - Multi-parameter distributed optical fiber sensing apparatus

Info

Publication number: WO2014183412A1
Application number: PCT/CN2013/087841
Authority: WO
Inventors: 吕立冬; 何金陵; 李垠韬; 梁云; 李炳林; 郭经红; 邓洁清; 任建伟
Original assignee: 国家电网公司; 中国电力科学研究院; 国网江苏省电力公司; 国网江苏省电力公司信息通信分公司; 国网冀北电力有限公司信通分公司
Priority date: 2013-05-17
Filing date: 2013-11-26
Publication date: 2014-11-20
Also published as: CN103323040A; CN103323040B

Abstract

A multi-parameter distributed optical fiber sensing apparatus comprises Brillouin optical time domain analysis meter and an optical time domain reflectometer. A pump light source used by a Brillouin optical time domain analysis technology and a detection light source required by an optical time domain reflection technology are coupled in a tested optical fiber through a coupler. The two laser light sources work in different wavelength ranges. Correspondingly, a Brillouin optical time domain analysis signal and an optical time domain reflection signal are separated out by a wavelength division multiplexer, then an optical signal separated out enters a photoelectric detector, and acquisition, operation, processing and display are performed by using an analog-to-digital conversion module, a signal processing module and a display module, and distributed measurement of a temperature and/or a stress, representation of the optical fiber and fault location are finally implemented.

Description

Multi-parameter distributed optical fiber sensing device

Technical field

The invention belongs to the field of sensing technology, and in particular relates to a multi-parameter distributed optical fiber sensing device.

Background technique

Distributed fiber optic sensing technology has important applications in fiber characterization, fault location, and monitoring of fiber ambient temperature, stress, and vibration. Optical time domain reflection technology, optical time domain analysis technology, and optical frequency domain analysis technology are several common techniques in distributed optical fiber sensing technology. However, each technology corresponds to less fiber sensing parameters, which is difficult to meet practical monitoring applications. The need to monitor multiple environmental parameters. For example, an optical time domain reflectometer based on optical time domain reflectometry can only characterize optical fibers, such as dispersion measurements, loss measurements, and fiber fault location, and cannot monitor the temperature and stress of the fiber environment. Although the Brillouin optical time domain reflectometer can realize temperature, stress monitoring and fiber fault location, it is difficult to use for fiber characterization and dispersion measurement, and it is difficult to obtain spatial resolution and high temperature and stress on the order of sub-meters. Resolution. Brillouin optical time domain analysis technology can achieve high spatial resolution and temperature and stress resolution compared with Brillouin optical time domain reflection technology, but it needs to inject pump light and continuous light from both ends of the fiber under test. Once the fiber under test breaks, the measurement system will not work.

In order to give full play to the characteristics of Brillouin optical time domain analysis technology, and avoid the shortcomings of the system that is difficult to locate faults when the fiber breaks, Liu Hangjie and others of Ningbo Nuochi Optoelectronic Technology Development Co., Ltd. applied for the patent "a searchable cloth". The Liyuan Optical Time Domain Analyzer (Patent Application No.: 201210189637.0) proposes to use the optical switch to connect the Brillouin optical time domain analyzer and the optical time domain reflectometer to the fiber under test, thereby achieving the temperature along the fiber under test. And / or stress measurement, so that once the fiber under test breaks, the optical time domain reflectometer can locate the break point. They simply connected the two devices through the optical switch to the fiber under test, without essentially integrating Brillouin optical time domain analysis technology and optical time domain reflection technology.

Summary of the invention

In view of the deficiencies of the prior art, the present invention proposes a multi-parameter distributed optical fiber sensing device that combines Brillouin optical time domain analysis technology and optical time domain reflection technology into a highly integrated distributed optical fiber sensing system. The system features distributed temperature, stress monitoring, fiber characterization, and fault location.

The invention provides a multi-parameter distributed optical fiber sensing device, which is improved in that the sensing device comprises: a first laser 1, a second laser 2, a first coupler 3a, a second coupler 3b, First electro-optic modulator 4a, a second electro-optic modulator 4b, a circulator 5, a first optical interface 6a, a second optical interface 6b, a wavelength division multiplexer 7, a photodetector 9, an analog-to-digital conversion module 10, a signal processing module 11 and a display module 12;

The laser light emitted by the first laser 1 is split into two paths by the first coupler 3a, and the first electro-optic modulator 4a is modulated into a pump light pulse, and is measured from the first optical interface 6a. One end of the optical fiber is injected, and the other is connected to the second electro-optic modulator 4b to generate a swept continuous detection light, which is then injected from the other end of the optical fiber via the second optical interface 6b;

The pumping light pulse interacts with the continuous probe light in the fiber under test to produce a stimulated Brillouin scattering effect, thereby transferring energy of the pumping light pulse to the continuous probe light;

The laser light emitted by the second laser 2 is modulated into a light pulse, and injected into the fiber to be tested through the first optical interface 6a, the light pulse generating back-scattered Rayleigh scattered light in the fiber under test;

The continuous probe light and the back-reverse Rayleigh light are sequentially transmitted to the photodetector 9 through the first optical interface 6a, the circulator 5, and the wavelength division multiplexer, The electrical signal outputted by the photodetector 9 is converted into a digital signal by the analog-to-digital conversion module 10, and then transmitted to the signal processing module 11 for processing, respectively, to obtain Brillouin optical time domain analysis data and optical time domain reflection data, and finally The display module 12 displays.

Wherein, the sensing device comprises an optical filter 8 for improving the signal to noise ratio of the Brillouin optical time domain analysis signal. Wherein, when the sensing device operates in the Brillouin optical time domain analysis mode and the optical time domain reflection mode at the same time, two photodetectors are selected, that is, the first photodetector 9a and the second photodetector 9b respectively receive the Buri The abundance time domain analysis signal and the optical time domain reflection signal, and the analog to digital conversion module 10 selects a dual channel data acquisition card to simultaneously extract Brillouin optical time domain analysis signals and optical time domain reflection signals.

Wherein, when the sensing device operates in the Brillouin optical time domain analysis mode or the optical time domain reflection mode, the same photodetector 9 is selected to receive the optical signal in the corresponding working mode.

Wherein, the sensing device comprises an erbium doped fiber amplifier 13 for amplifying the peak power of the pump light pulse. Wherein the sensing device comprises a first laser driver lb and a third laser la;

The first laser driver lb is selected to drive the third laser la to generate continuous probe light.

Wherein the sensing device comprises a third coupler 3c:

When the first laser 1 and the second laser 2 are alternately operated, the coupler 3c is used to couple the optical signal separated from the wavelength division multiplexer 7;

When the first laser 1 is in operation, continuous probe light amplified by the stimulated Brillouin scattering effect is separated by the wavelength division multiplexer 7, and filtered by the optical filter 8 to enter the third The coupler 3c is finally received by the photodetector 9; When the second laser 2 is in operation, the light pulse from the second laser 2 is separated from the Rayleigh scattered light in the fiber under test by the wavelength division multiplexer 7 and then enters the third coupler 3c. Finally received by the photodetector 9;

The analog-to-digital conversion module 10 uses a single-channel data acquisition card to collect the electrical signals output by the photodetector 9, and then transmits the signals to the signal processing module 11.

The first electro-optic modulator 4a is used to modulate the continuous light output by the first laser 1 and the second laser 2, thereby obtaining pump light pulses and optical time domain reflections in Brillouin optical time domain analysis mode. Probe light pulse in mode.

Wherein the sensing device comprises a second laser driver 2a:

The second laser driver 2a is selected to drive the second laser 2 to generate a light pulse that is coupled to the fiber under test through the second coupler 3b from the pump light pulse from the first laser 1.

The second laser driver 2a drives the second laser 2 to linearly change its output wavelength to achieve characterization and fault location of the fiber under test.

Compared with the prior art, the beneficial effects of the present invention are:

The invention integrates optical time domain analysis technology and optical time domain reflection technology into a distributed optical fiber sensing device, realizes measurement of temperature and stress along the optical fiber under test, and fiber characterization and fault location. Therefore, it combines two kinds of transmissions. The advantages of sensing technology, multi-parameter fiber sensing in a compact system, with distinct technical features and practical value.

DRAWINGS

1 is a schematic structural view of a multi-parameter distributed optical fiber sensing device according to a first embodiment.

2 is a schematic structural view of a multi-parameter distributed optical fiber sensing device according to a second embodiment.

3 is a schematic structural view of a multi-parameter distributed optical fiber sensing device according to a third embodiment.

4 is a schematic structural view of a multi-parameter distributed optical fiber sensing device according to a fourth embodiment.

FIG. 5 is a schematic structural diagram of a multi-parameter distributed optical fiber sensing device according to a fifth embodiment.

6 is a schematic structural view of a multi-parameter distributed optical fiber sensing device according to a sixth embodiment.

FIG. 7 is a schematic structural diagram of a multi-parameter distributed optical fiber sensing device according to a seventh embodiment.

FIG. 8 is a schematic structural diagram of a multi-parameter distributed optical fiber sensing device according to an eighth embodiment.

detailed description The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

The multi-parameter distributed optical fiber sensing device provided by the embodiment provides the advantages of the two sensing technologies to realize multi-parameter optical fiber sensing in a compact system, and the device comprises:

a first laser 1 for providing pump light and probe light required by Brillouin optical time domain analysis technology; a third laser la for generating continuous light for sweeping;

a first laser driver lb for driving the laser la;

a second laser 2 for providing probe light required for optical time domain reflection technology;

a second laser driver 2a for driving the laser 2 to generate a light pulse required for the optical time domain reflection technique; a first coupler 3a for splitting the light from the laser 1 into two paths;

a second coupler 3b for coupling light from the laser 1 and the laser 2 into one way;

a third coupler 3c, configured to couple the Brillouin optical time domain analysis signal and the optical time domain reflection signal into a path; the first electro-optic modulator 4a is configured to modulate the continuous light into a light pulse;

a second electro-optic modulator 4b, configured to frequency shift the continuous light to output the swept continuous light;

a first optical interface 6a for optical fiber connection;

a second optical interface 6b for optical fiber connection;

a wavelength division multiplexer 7 for separating Brillouin optical time domain analysis signals and optical time domain reflection signals;

The optical filter 8 is used for improving the optical signal to noise ratio of the Brillouin optical time domain analysis signal;

Photodetector 9, for photoelectric conversion;

a first photodetector 9a for receiving a Brillouin optical time domain analysis signal;

a second photodetector 9b for receiving an optical time domain reflection signal;

An analog to digital conversion module 10, configured for photoelectric signal acquisition;

The signal processing module 11 is configured to process the digital electrical signals to obtain a Brillouin optical time domain analysis curve and an optical time domain reflection curve, respectively;

The display module 12 is configured to display the measurement result.

Erbium-doped fiber amplification 13, used to boost the peak power of the optical pulse;

Example 1

Referring to FIG. 1 , a multi-parameter distributed optical fiber sensing device provided by the embodiment is as follows: The Brillouin optical time domain analysis mode and the optical time domain reflection mode of the multi-parameter distributed optical fiber sensing device are At the same time, the structure and working process of the Brillouin optical time domain analysis mode are as follows:

The laser light emitted by the single-frequency first laser 1 is split into two paths through the first coupler 3a, and is transmitted to the second coupler 3b. An input terminal is further outputted by the second coupler 3b and then enters the first electro-optic modulator 4a. The first electro-optic modulator 4a operates in a pulse modulation mode, and the output thereof is a pump required in Brillouin optical time domain analysis technology. a pulse of light, the light pulse is accessed from the port 1 of the circulator 5, and the fiber to be tested is injected from the first optical interface 6a via the 2 port of the circulator 5, and the other path outputted from the first coupler 3a is connected to the second The electro-optic modulator 4b, the second electro-optic modulator 4b operates in a frequency sweep mode, and the output thereof is continuous detection light required in Brillouin optical time domain analysis technology, and the probe light is injected into the measured second optical interface 6b. The other end of the fiber;

The pump light pulse interacts with the continuous probe light to produce a stimulated Brillouin scattering effect such that the continuous probe light is distributedly amplified;

The distributed probe light that is distributed and amplified enters the 2-port of the circulator 5, and is output from the 3-port of the circulator 5 to enter the wavelength division multiplexer 7, and then outputs a light from a port of the wavelength division multiplexer 7. Filter 8 to filter out optical noise other than the wavelength of the probe light;

The probe light outputted from the optical filter 8 enters the first photodetector 9a and is converted into an electrical signal. The electrical signal is input to a signal acquisition end of the analog-to-digital conversion module 10. The analog-to-digital conversion module 10 uses a dual-channel data acquisition card. The analog electrical signal is converted into a digital signal;

The signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and obtains a Brillouin optical time domain analysis curve through a corresponding digital signal processing algorithm, and finally displays by the display module 12;

The structure and working process of the device in the optical time domain reflection mode are as follows:

The laser light from the second laser 2 is transmitted to the other input end of the second coupler 3b, the output end of the second coupler 3b is connected to the first electro-optic modulator 4a, and the first electro-optic modulator 4a will laser the laser from the second laser 2. Modulated into a probe light pulse required in the optical time domain reflection technique, the probe light pulse enters from the port 1 of the circulator 5, is output through the 2-port of the circulator 5, and is injected from one end of the fiber to be tested through the first optical interface 6a. ;

The detection light pulse from the second laser 2 is returned to the 2 port of the circulator 5 from the back Rayleigh scatter signal generated in the fiber under test, and then connected to the wavelength division multiplexer 7 from the 3 port of the circulator 5, and from The other output end of the wavelength division multiplexer 7 outputs directly into the second photodetector 9b;

The second photodetector 9b converts the optical signal into an electrical signal, the electrical signal is connected to another signal collecting end of the analog-to-digital conversion module 10, and the analog-to-digital conversion module 10 uses a dual-channel data acquisition card;

The signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and obtains an optical time domain reflection curve through a corresponding digital signal processing algorithm, and finally displays by the display module 12;

Example 2

2 is a multi-parameter distributed optical fiber sensing device provided by an embodiment of the present invention, and the detailed content of the device is as follows. Next:

The Brillouin optical time domain analysis mode and the optical time domain reflection mode of the multi-parameter distributed optical fiber sensing device cannot be simultaneously turned on. When the device turns on the Brillouin optical time domain analysis mode, the device structure and its working process are as follows:

The laser light emitted by the single-frequency first laser 1 is split into two paths through the first coupler 3a, one connected to one input end of the second coupler 3b, and then outputted through the second coupler 3b to enter the first electro-optic modulator 4a, An electro-optic modulator 4a operates in a pulse modulation mode, the output of which is a pump light pulse required in Brillouin optical time domain analysis technology, which is accessed from port 1 of the circulator 5 and via the circulator 5 The second port is injected from the first optical interface 6a into the fiber under test, and the other light output from the first coupler 3a is connected to the second electro-optic modulator 4b. The second electro-optic modulator 4b operates in the sweep mode, and its output is Buri. Continuous detection light required in the time-domain analysis technique, the detection light is injected into the other end of the fiber under test via the second optical interface 6b;

The distributed probe light that is distributed and amplified enters the 2-port of the circulator 5, and is output from the 3-port output of the circulator 5 into the wavelength division multiplexer 7, and then is output from a port of the wavelength division multiplexer 7 into an optical filter. 8 to filter out optical noise other than the wavelength of the probe light;

The probe light output from the optical filter 8 is transmitted to the input end of the third coupler 3c, and the output end thereof is connected to the photodetector 9, the photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is connected to the analog-to-digital conversion module. a signal acquisition end of 10, the analog to digital conversion module 10 converts the analog electrical signal into a digital signal;

When the device turns on the light time domain reflection mode, the device structure and its working process are as follows:

The laser light from the second laser 2 is transmitted to the other input end of the second coupler 3b, the output end of the second coupler 3b is connected to the first electro-optic modulator 4a, and the first electro-optic modulator 4a will laser the laser from the second laser 2. Modulating into a probe light pulse required in the optical time domain reflection technique, and entering from the port 1 of the circulator 5, outputting through the 2-port of the circulator 5, and then injecting from one end of the fiber to be tested through the first optical interface 6a;

The back-scattered Rayleigh scatter signal generated by the probe light pulse from the second laser 2 in the fiber under test returns to the 2 port of the circulator 5, and is output from the 3-port output of the circulator 5 into the wavelength division multiplexer 7, and then The other output of the wavelength division multiplexer 7 is output and then connected to a third coupler 3c, through the output of the third coupler 3c into the photodetector 9;

The photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is connected to the signal collecting end of the analog-to-digital conversion module 10; The signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and obtains an optical time domain reflection curve through a corresponding digital signal processing algorithm, and finally displays by the display module 12;

Example 3

Referring to FIG. 3, a multi-parameter distributed optical fiber sensing device provided by an embodiment of the present invention has the following details:

The Brillouin optical time domain analysis mode and the optical time domain reflection mode of the multi-parameter distributed optical fiber sensing device can be simultaneously turned on. The structure and working process of the device in Brillouin optical time domain analysis mode are as follows:

The laser light emitted by the single-frequency first laser 1 is split into two paths through the first coupler 3a, and enters the first electro-optic modulator 4a. The first electro-optic modulator 4a operates in a pulse modulation mode, and the output thereof is a Brillouin optical time domain. The pump light pulse required in the analysis technique is amplified by the erbium-doped fiber amplifier 13 and then connected to the second coupler 3b, and then outputted from the second coupler 3b and then enters the port 1 of the circulator 5, and passes through the ring. The second port of the device 5 is injected from the first optical interface 6a into the fiber under test, and the other light output from the first coupler 3a is connected to the second electro-optic modulator 4b. The second electro-optic modulator 4b operates in the sweep mode, and its output The continuous probe light required in the Brillouin optical time domain analysis technique, the probe light is injected into the other end of the fiber under test via the second optical interface 6b;

The distributed probe light that is distributed and amplified enters the 2-port of the circulator 5, and is output from the 3-port of the circulator 5 into the wavelength division multiplexer 7, and then enters an optical filter from a port output of the wavelength division multiplexer 7. 8 to filter out optical noise other than the wavelength of the probe light;

The probe light outputted from the optical filter 8 enters the first photodetector 9a and is converted into an electrical signal. The electrical signal is input to a signal acquisition end of the analog-to-digital conversion module 10. The analog-to-digital conversion module 10 uses a dual-channel data acquisition card. Converting an analog electrical signal into a digital signal;

The second laser driver 2a drives the second laser 2 to generate a light pulse which is input to the other input of the second coupler 3b, and then outputs from the second coupler 3b to the port 1 of the circulator 5, and via the circulator 5 The 2-port output is injected from one end of the fiber to be tested through the first optical interface 6a;

The detection light pulse from the second laser 2 is returned to the 2 port of the circulator 5 via the back-direction Rayleigh scatter signal generated in the fiber under test, and is connected to the wavelength division multiplexer 7 through the 3-port of the circulator 5, and then from Wavelength division multiplexer 7 The other output terminal outputs directly into the second photodetector 9b _;

The signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and obtains an optical time domain analysis curve through a corresponding digital signal processing algorithm, and finally displays by the display module 12;

Example 4

Referring to FIG. 4, a multi-parameter distributed optical fiber sensing device provided by an embodiment of the present invention has the following details:

The probe light output from the optical filter 8 is transmitted to the input end of the third coupler 3c, and the output end thereof is connected to the photodetector 9, and the photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is connected to the analog-to-digital conversion module. The signal acquisition end of 10, the analog to digital conversion module 10 converts the analog electrical signal into a digital signal;

When the device turns on the light time domain reflection mode, the device structure and working process are as follows:

The second laser driver 2a drives the second laser 2 to generate a light pulse which is input to the other input of the second coupler 3b, and then outputs from the second coupler 3b to the port 1 of the circulator 5, and via the circulator 5 2 After the port is output, the first optical interface 6a is injected from one end of the optical fiber to be tested;

The detection light pulse from the second laser 2 is returned to the 2 port of the circulator 5 at the back Rayleigh scatter signal generated in the fiber under test, and is output from the 3 port of the circulator 5 and enters the wavelength division multiplexer 7, and then After outputting from the other output end of the wavelength division multiplexer 7, the third coupler 3c is connected, and the output end of the third coupler 3c enters the photodetector 9;

The photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is input to the signal collecting end of the analog-to-digital conversion module 10; the signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and passes the corresponding digital signal processing algorithm. Obtaining an optical time domain reflection curve, which is finally displayed by the display module 12;

Example 5

FIG. 5 is a multi-parameter distributed optical fiber sensing device according to an embodiment of the present invention. The details of the device are as follows:

The Brillouin optical time domain analysis mode and the optical time domain reflection mode of the multi-parameter distributed optical fiber sensing device can be simultaneously turned on, and the structure and working process of the device in the Brillouin optical time domain analysis mode are as follows:

The laser light from the single-frequency first laser 1 is input to the first coupler 3a, and is output through the first coupler 3a to enter the first electro-optic modulator 4a. The first electro-optic modulator 4a operates in a pulse modulation mode, and its output is Buri. Pump light pulse required in the time-domain analysis technique, the light pulse is accessed from the port 1 of the circulator 5, and is injected into the fiber under test via the 2 port of the circulator 5 from the first optical interface 6a;

The first laser driver lb linearly drives the third laser la to generate the continuous probe light required in the Brillouin optical time domain analysis technique, and the probe light is injected into the other end of the fiber under test via the second optical interface 6b;

The structure and working process of the device in the optical time domain reflection mode are as follows: The laser light from the second laser 2 is transmitted to the other input end of the first coupler 3a, the output of the first coupler 3a is connected to the first electro-optic modulator 4a, and the first electro-optic modulator 4a is to laser from the second laser 2. Modulating into a probe light pulse required in the optical time domain reflection technique, and entering from the port 1 of the circulator 5, outputting through the 2-port of the circulator 5, and then injecting from one end of the fiber to be tested through the first optical interface 6a;

The detection light pulse from the second laser 2 is returned to the 2 port of the circulator 5 from the back Rayleigh scatter signal generated in the fiber under test, and is input to the wavelength division multiplexer 7 from the 3 port of the circulator 5, and then from the wave. The other output end of the sub-multiplexer 7 outputs directly to the second photodetector 9b _;

Example 6

FIG. 6 is a multi-parameter distributed optical fiber sensing device according to an embodiment of the present invention. The details of the device are as follows:

The laser light from the single-frequency first laser 1 is input to the first electro-optic modulator 4a, and the first electro-optic modulator 4a operates in a pulse modulation mode, and the output thereof is a pump light pulse required in Brillouin optical time domain analysis technology. The optical pulse is amplified by the erbium-doped fiber amplifier 13 and then connected to the first coupler 3a, and then outputted from the first coupler 3a and then enters the port 1 of the circulator 5, and is output from the first light via the 2-port of the circulator 5 The interface 6a is injected into the fiber under test;

The distributed probe light that is distributed and amplified enters the 2 port of the circulator 5, enters the wavelength division multiplexer 7 from the 3 port of the circulator 5, and then enters an optical filter from a port of the wavelength division multiplexer 7. 8 to filter out optical noise other than the wavelength of the probe light;

The probe light outputted from the optical filter 8 enters the first photodetector 9a and is converted into an electrical signal. The electrical signal is input to a signal acquisition end of the analog-to-digital conversion module 10. The analog-to-digital conversion module 10 uses a dual-channel data acquisition card. Converting an analog electrical signal into a digital signal; The signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and obtains a Brillouin optical time domain analysis curve by a corresponding digital signal processing algorithm, and finally displays by the display module 12;

The second laser driver 2a drives the second laser 2 to generate a light pulse which is input to the other input of the first coupler 3a, and then outputs from the first coupler 3a to the port 1 of the circulator 5, and via the circulator 5 The 2-port output is injected from one end of the fiber to be tested through the first optical interface 6a;

The second photodetector 9b converts the optical signal into an electrical signal, the electrical signal is input to another signal collecting end of the analog to digital conversion module 10, and the analog to digital conversion module 10 uses a dual channel data acquisition card;

Example 7

7 is a multi-parameter distributed optical fiber sensing device provided by an embodiment of the present invention. The details of the device are as follows:

The laser light from the single-frequency first laser 1 is input to the first electro-optic modulator 4a, and the first electro-optic modulator 4a operates in a pulse modulation mode, and the output thereof is a pump light pulse required in Brillouin optical time domain analysis technology. The optical pulse is amplified by the erbium-doped fiber amplifier 13 and then connected to the first coupler 3a, and then outputted from the first coupler 3a and then enters the port 1 of the circulator 5, and from the first optical interface 6a via the 2-port of the circulator 5 Injecting the fiber under test;

The distributed probe light that is distributed and amplified enters the 2 port of the circulator 5, enters the wavelength division multiplexer 7 from the 3 port of the circulator 5, and then enters an optical filter 8 from a port of the wavelength division multiplexer 7. Filtering out optical noise outside the wavelength of the probe light;

The probe light output from the optical filter 8 is transmitted to the input terminal of the third coupler 3c, and its output terminal is connected to the photodetection. The photodetector 9 converts the optical signal into an electrical signal, the electrical signal is input to the signal collecting end of the analog-to-digital conversion module 10, and the analog-to-digital conversion module 10 converts the analog electrical signal into a digital signal;

The back-scattered Rayleigh scatter signal generated by the probe light pulse from the second laser 2 in the fiber under test is returned from the 3-port output of the circulator 5 via the 2-port of the circulator 5 and enters the wavelength division multiplexer 7, and the wave is received from the wave. The other output end of the sub-multiplexer 7 is outputted and then input to the third coupler 3c, and output to the photodetector 9 through the third coupler 3c;

The photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is input to the signal collecting end of the analog-to-digital conversion module 10; the signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and obtains the data through the corresponding digital signal processing algorithm. The optical time domain reflection curve is finally displayed by the display module 12;

Example 8

FIG. 8 is a multi-parameter distributed optical fiber sensing device according to an embodiment of the present invention. The details of the device are as follows:

The laser light from the single-frequency first laser 1 is input to the first coupler 3a, and is output through the first coupler 3a to enter the first electro-optic modulator 4a. The first electro-optic modulator 4a operates in a pulse modulation mode, and its output is Buri. a pump light pulse required in the time-domain analysis technique, the light pulse is accessed from the port 1 of the circulator 5, and the fiber to be tested is injected from the first optical interface 6a via the 2-port of the circulator 5;

The first laser driver lb linearly drives the third laser la to generate the probe light required in the Brillouin optical time domain analysis technique, and the probe light is injected into the other end of the fiber under test via the second optical interface 6b;

The distributed probe light that is distributed and amplified is input from the 2-port of the circulator 5, and enters the wavelength division multiplexer 7 from the 3-port of the circulator 5, and then is output from a port of the wavelength division multiplexer 7 into an optical filter. 8 to filter out optical noise other than the wavelength of the probe light; The probe light output from the optical filter 8 is transmitted to the input end of the third coupler 3c, and the output end thereof is connected to the photodetector 9, and the photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is connected to the analog-to-digital conversion module. The signal acquisition end of 10, the analog to digital conversion module 10 converts the analog electrical signal into a digital signal;

The laser generated by the second laser 2 is connected to the other input end of the first coupler 3a, the output of the first coupler 3a is connected to the first electro-optic modulator 4a, and the electro-optic modulator operates in a pulse modulation mode, and the output of the optical pulse Entering the port 1 of the circulator 5 and outputting it through the 2 port of the circulator 5 and then injecting from one end of the fiber to be tested through the first optical interface 6a; the optical pulse returns to the Rayleigh scatter signal generated in the fiber under test. The port 2 of the circulator 5 is outputted from the 3-port of the circulator 5 into the wavelength division multiplexer 7, and then outputted from the other output of the wavelength division multiplexer 7 and then connected to the third coupler 3c. The three coupler 3c output enters the photodetector 9;

The photodetector 9 converts the optical signal into an electrical signal, and the electrical signal is input to the signal collecting end of the analog-to-digital conversion module 10; the signal processing module 11 receives the data transmitted from the analog-to-digital conversion module 10, and passes the corresponding digital signal processing algorithm. An optical time domain reflection curve is obtained, which is finally displayed by display module 12.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be The invention is to be construed as being limited to the scope of the appended claims.

Claims

Rights request

1. A multi-parameter distributed optical fiber sensing device, characterized in that the sensing device includes: a first laser (1), a second laser (2), a first coupler (3a), a second coupler (3b), first electro-optical modulator (4a), second electro-optical modulator (4b), circulator (5), first optical interface (6a), second optical interface (6b), wavelength division multiplexer ( 7), photodetector (9), analog-to-digital conversion module (10), signal processing module (11) and display module (12); the laser emitted by the first laser (1) is passed by the first coupler (3a) Divided into two channels, one channel is connected to the first electro-optical modulator (4a) to be modulated into a pump light pulse, and is injected from one end of the optical fiber under test through the first optical interface (6a), while the other channel is connected to the optical fiber under test. The second electro-optical modulator (4b) is used to generate sweep-frequency continuous detection light, which is then injected from the other end of the optical fiber through the second optical interface (6b);

The interaction between the pump light pulse and the continuous detection light in the optical fiber under test produces the stimulated Brillouin scattering effect, thereby transferring the energy of the pump light pulse to the continuous detection light;

The laser light emitted by the second laser (2) is modulated into a light pulse and injected into the optical fiber under test through the first optical interface (6a). The optical pulse generates back-Rayleigh scattered light in the optical fiber under test;

The continuous detection light and the back-Rayleigh scattered light are transmitted to the photoelectric device through the first optical interface (6a), the circulator (5) and the wavelength division multiplexer (7) in sequence. The electrical signal output by the detector (9) and the photodetector (9) is converted into a digital signal by the analog-to-digital conversion module (10), and then transmitted to the signal processing module (11) for processing, and the BRI is obtained respectively. The optical time domain analysis data and optical time domain reflection data are finally displayed by the display module (12).

2. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that the sensing device includes an optical filter (8) for improving the signal of the Brillouin optical time domain analysis signal. noise ratio.

3. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that when the sensing device works in the Brillouin optical time domain analysis mode and the optical time domain reflection mode at the same time, two The photodetectors, that is, the first photodetector (9a) and the second photodetector (9b) respectively receive the Brillouin optical time domain analysis signal and the optical time domain reflection signal, and the analog-to-digital conversion module (10) adopts dual Channel data acquisition card to simultaneously extract Brillouin optical time domain analysis signal and optical time domain reflection signal.

4. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that when the sensing device works in the Brillouin optical time domain analysis mode or the optical time domain reflection mode, the same one is selected. The photodetector (9) is used to receive light signals in corresponding working modes.

5. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that, the sensing The device includes an erbium-doped fiber amplifier (13) for amplifying the peak power of the pump light pulse.

6. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that the sensing device includes a first laser driver (lb) and a third laser (la);

The first laser driver (lb) is selected to drive the third laser (la) to generate continuous detection light.

7. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that the sensing device includes a third coupler (3c):

When the first laser (1) and the second laser (2) work alternately, the coupler (3c) is used to couple the optical signal separated from the wavelength division multiplexer (7);

When the first laser (1) is working, the continuous detection light amplified by the stimulated Brillouin scattering effect is separated by the wavelength division multiplexer (7), and then filtered by the optical filter (8) Then enters the third coupler (3c), and is finally received by the photodetector (9);

When the second laser (2) is working, the back-Rayleigh scattered light from the second laser (2) in the optical fiber under test is separated by the wavelength division multiplexer (7) and then enters the optical fiber. The third coupler (3c) is finally received by the photodetector (9);

The analog-to-digital conversion module (10) uses a single-channel data acquisition card to collect the electrical signal output by the photodetector (9), and then transmits it to the signal processing module (11) for processing.

8. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that the first electro-optical modulator (4a) is selected to modulate the first laser (1) and the second laser (2) Output continuous light, thereby obtaining pump light pulses in the Brillouin optical time domain analysis mode and detection light pulses in the optical time domain reflection mode.

9. A multi-parameter distributed optical fiber sensing device according to claim 1, characterized in that the sensing device includes a second laser driver (2a):

The second laser driver (2a) is selected to drive the second laser (2) to generate light pulses, and the light pulses and the pump light pulses from the first laser (1) pass through the second coupler (3b ) is coupled into the optical fiber under test.

10. A multi-parameter distributed optical fiber sensing device according to claim 9, characterized in that the second laser driver (2a) drives the second laser (2) to linearly change its output wavelength to Realize the characterization and fault location of the optical fiber under test.