WO2013079027A1

WO2013079027A1 - Distributed fibre sensing device based on dual channel and running method thereof

Info

Publication number: WO2013079027A1
Application number: PCT/CN2012/085707
Authority: WO
Inventors: 杜兵
Original assignee: 西安金和光学科技有限公司
Priority date: 2011-12-02
Filing date: 2012-12-01
Publication date: 2013-06-06
Also published as: CN103134533A; CN103134533B

Abstract

A distributed fibre sensing device based on dual channel. The employed fibre (11) is a fibre having two optical signal transmission channels (15, 16), such as a dual-core fibre, a dual-cladding or multi-cladding fibre. The optical signal has different speeds in the two optical signal transmission channels (15, 16). The purpose of monitoring a physical quantity to be detected in a distributed way can be realized by detecting the change in the optical signal between the two optical signal transmission channels (15, 16) and the relative position of each optical signal. The fibre sensing device has the advantages of being convenient in use, low in costs, and high in accuracy. Also provided are four running methods for a distributed fibre sensing device based on dual channel.

Description

Dual-channel distributed optical fiber sensing device and operating method thereof

Technical field

The invention relates to an optical fiber sensing device and a method for operating the same, and particularly to a distributed based on monitoring a change of a forward transmission optical signal with two channels Optical fiber sensing device and its operating method.

Background technique

China Patent Application No. 201120130642.5 "Twin-fiber-based temperature sensing device" patent discloses a temperature sensing device that uses a broadband source, a dual-core fiber, and a spectrum analyzer. When the temperature changes, two of the two-core fibers The distance between the cores also changes, causing the core of the broadband optical signal to be coupled to the wavelength of the optical signal of the core to which the optical signal is not injected, and detecting the change by the optical spectrum analyzer, thereby completing the temperature The monitoring is simple in structure and wide in test range, but its test parameters are single and distributed monitoring cannot be realized.

Existing distributed or quasi-distributed optical fiber sensing devices are mainly inspection devices for backscattered light in optical fibers, including the most commonly used optical time domain reflectometry (OTDR), fiber Raman temperature sensing devices, Brillouin scattering sensing device and Bragg fiber grating sensing device. In the first three sensing devices, since the backscattered light containing the sensing information in the optical fiber is small relative to the incident light, the general backscattered light ratio The incident light is three to six orders of magnitude smaller, so the detection of backscattered light is difficult. In order to remove the noise, it is often necessary to sample the integrator many times to extract the weak signal, so that the monitoring equipment is more complicated, the cost is higher, and the real-time performance is poor. Moreover, the maximum distance for monitoring is less than 100 km; while the quasi-distributed optical fiber sensing device composed of Bragg fiber grating has strong reflected light signal, the optical signals between the fiber gratings easily interfere with each other, so the optical fiber The number of gratings is small, and the number of fiber gratings on each fiber is only a few dozen at most, making it difficult to achieve long-distance distributed monitoring.

On the other hand, the existing optical fiber communication technology is developing at a rapid speed, and the distance of its non-relay communication is easily more than several hundred kilometers. If the erbium-doped or Raman fiber amplification device is used up to thousands of kilometers, the main reason is The intensity of the transmitted optical signal is much greater than that of the backscattered optical signal. If there is a distributed sensing device that monitors the change of the optical signal based on forward transmission, the distance of the distributed optical fiber monitoring can be greatly extended. Such a device is currently not retrieved.

technical problem

The invention discloses a dual-channel distributed optical fiber sensing device and an operating method thereof. The optical fiber used is an optical fiber having two optical signal transmission channels, such as a dual-core optical fiber, a double-clad layer or a multi-clad fiber. Distributed monitoring can be achieved by detecting changes in optical signals between two transmitted optical signal channels. The optical fiber sensing device has the advantages of convenient use, low cost and good application prospect.

Technical solution

In order to solve the above technical problems, the technical solution adopted by the present invention is:

Dual-channel distributed optical fiber sensing device The utility model comprises a control module, a light source module, a coupler, a photodetector module and a processing module. The control module is connected with the light source module and controls the latter to emit a pulsed light signal, and the light source module is connected with the coupler, and the coupler is Connected to one end of the sensing fiber, the sensing fiber is an optical fiber including an optical channel 1 and an optical channel 2. The coupler is configured to couple the optical signal into only one of the optical channels in the sensing fiber. The coupler, the optical signal of the same wavelength transmits different speeds in the optical channel 1 and the optical channel 2; the other end of the sensing fiber is connected to the photodetector, and the photodetector simultaneously acquires the optical channel The optical signal transmitted in the optical channel 2 is connected to the processing module.

Further, the other end of the sensing fiber is connected to the coupler 2, and the coupler 2 includes a channel 1 and a channel 2, and the channel 1 and the channel 2 do not interfere with each other, and the optical channel in the sensing fiber is One is connected to the channel in the coupler 2, and the channel is connected to the photodetector; the optical channel 2 in the sensing fiber is connected to the channel 2 in the coupler 2, and the channel is combined with the photodetector Connection; the photodetector 1 and the photodetector 2 are connected to the processing module.

The utility model further comprises a 1×2 optical coupler disposed between the light source module and the coupler, the light source module is connected with the 1-port end of the 1×2 optical coupler, and the end of the 2-port of the 1×2 optical coupler is coupled with the coupler. One end of the two ports of the 1×2 optical coupler is connected to the light detecting module three, and the light detecting module three is connected to the control module.

The 1×2 optical coupler is an optical splitter with a 1:99 optical signal distribution ratio, wherein one end of the optical signal distribution is connected to the coupler, and the end with less light signal is connected to the light detecting module 3.

The utility model further comprises a communication fiber disposed in parallel with the sensing fiber. The two ends of the communication fiber are respectively connected with the transceiver module and the transceiver module, and the transceiver module 1 and the transceiver module 2 are respectively connected with the control module and the processing module.

The photodetector 1, the photodetector 2, and the photodetecting module 3 are one of an optical power meter, a photon counter, a spectrum analyzer, and a wavelength meter.

The light source module is one of a single wavelength light source, a multi-wavelength light source or a broadband light source.

The sensing fiber is a W-type fiber, and the core, the cladding layer, the cladding layer 2 and the cladding layer 3 are sequentially distributed from the center to the edge, and the core has a refractive index greater than that of the cladding layer. The refractive index of the cladding layer 2 is greater than the refractive index of the cladding layer 1 and the cladding layer 3, and is a protective layer on the outer side of the cladding layer 3; the core layer and the cladding layer 2 are respectively optical channels of the sensing fiber One and two optical channels.

The sensing fiber is a dual-core fiber The inner cladding layer and the outer cladding layer on the outer side of the inner cladding layer are arranged with the core one and the core core side by side in the inner cladding layer. The refractive index of the core one and the core two is greater than the refractive index of the inner cladding layer, and the inner cladding layer The refractive index is greater than the refractive index of the outer cladding layer, and is coated on the outer side of the outer cladding layer; the core one and the core core two are the optical channel one and the optical channel two of the sensing fiber, respectively.

At least the region between the optical channel 1 and the optical channel 2 is a fluorescent cladding region, and the fluorescent cladding region is composed of a transparent material doped with a fluorescent material.

The refractive index of the core 1 is higher than the refractive index of the core 2.

The outer diameter of the core 1 is larger than the outer diameter of the core 2.

The core one and the core two are disposed in the inner cladding in a spiral form.

The core is located on a central axis of the optical fiber, and the core 2 is disposed around the core.

The operation method of the dual-channel distributed optical fiber sensing device is as follows:

1 The control module controls the light source module to emit a pulsed light signal, and the pulsed light signal is injected into the optical channel of one end of the sensing fiber through the coupler;

2 The pulsed optical signal is transmitted from one end of the sensing fiber to the other end in the optical channel, and is acquired by the optical detecting module disposed at the other end of the sensing fiber, and the optical detecting module converts the pulsed optical signal into an electrical signal transmission. Give the processing module;

3 When a certain part of the sensing fiber is changed by the physical quantity to be measured, the optical signal transmitted in the optical channel is partially coupled into the optical channel 2 and transmitted in the optical channel 2, since the optical channel 1 and the optical channel 2 The transmission speeds of the internal optical signals are different, and the optical signals in the optical channel 1 and the optical channel are sequentially sequenced to the other end of the sensing fiber and acquired by the optical detecting module. The optical detecting module converts the acquired optical signal into an electrical signal transmission. To the processing module, the processing module calculates the size and position of the physical quantity to be measured according to the size and time interval of the electrical signal, thereby completing the purpose of distributed monitoring.

Based on a two-channel distributed optical fiber sensing device, the steps are as follows:

2 The pulsed optical signal is transmitted from one end of the sensing fiber to the other end in the optical channel, and the coupler 2 is disposed at the other end of the sensing fiber. The channel 1 in the coupler 2 is connected to the optical channel, and the other end of the channel is The optical detecting module is connected, the channel 2 in the coupler 2 is connected to the optical channel 2, and the other end of the channel 2 is connected to the optical detecting module 2. The optical detecting module 1 and the optical detecting module 2 respectively transmit the optical channel 1 and the optical channel 2 The pulsed optical signal is converted into an electrical signal and transmitted to the processing module;

3 When a certain part of the sensing fiber is changed by the physical quantity to be measured, the optical signal transmitted in the optical channel is partially coupled into the optical channel 2 and transmitted in the optical channel 2, since the optical channel 1 and the optical channel 2 The transmission speeds of the internal optical signals are different, and the optical signals in the optical channel 1 and the optical channel 2 are sequentially obtained at the other end of the sensing fiber and are respectively acquired by the optical detecting module 1 and the optical detecting module 2. The optical detecting module 1 and the optical detecting module 2 respectively The acquired optical signal is converted into an electrical signal and transmitted to the processing module, and the processing module calculates the size and position of the physical quantity to be measured according to the order, size and time interval of the electrical signal, thereby completing the purpose of distributed monitoring.

Further, in step 3), The utility model further comprises a 1×2 optical coupler disposed between the light source module and the coupler, the light source module is connected with the 1-port end of the 1×2 optical coupler, and the end of the 2-port of the 1×2 optical coupler is coupled with the coupler. Connected, one end of the two ports of the 1×2 optical coupler is connected to the light detecting module three, and the light detecting module three is connected with the control module; the pulsed light signal emitted by the light source module passes through the 1×2 optical coupler and a small part enters the light. The detecting module 3, the light detecting module 3 converts the signal into an electrical signal and transmits the signal to the control module, and the control module calculates the size of the pulsed light signal emitted by the light source module according to the electrical signal and converts the value into a preset code, and controls The module controls the light source module to send the code; the light detecting module 2 obtains the optical signal containing the code and converts it into an electrical signal and transmits the signal to the processing module, and the processing module compares the code with the preset code table to obtain the pulse light of the light source module. The size of the signal, such as the power level of the pulsed light signal, the wavelength state, and the magnitude and position of the physical quantity to be measured are calculated according to the value.

Further, in step 3), The utility model further comprises a 1×2 optical coupler disposed between the light source module and the coupler, the light source module is connected with the 1-port end of the 1×2 optical coupler, and the end of the 2-port of the 1×2 optical coupler is coupled with the coupler. Connected, one end of the two ports of the 1×2 optical coupler is connected to the light detecting module three, and the light detecting module three is connected with the control module; the pulsed light signal emitted by the light source module passes through the 1×2 optical coupler and a small part enters the light. The detecting module 3, the light detecting module 3 converts the signal into an electrical signal and transmits the signal to the control module, and the control module calculates the size of the pulsed light signal emitted by the light source module according to the electrical signal and converts the value into a preset code, and controls The module control transceiver module sends the code through the communication fiber; the transceiver module 2 obtains the encoded optical signal through the communication fiber and converts it into an electrical signal and transmits it to the processing module, and the processing module compares the code with the preset code table to obtain the light source. The module sends out the size of the pulsed optical signal, such as the power level or wavelength state of the pulsed optical signal, and calculates the magnitude and position of the physical quantity to be measured according to the value. Correction.

Method for operating distributed optical fiber sensing device based on dual channel The sensing fiber has a fluorescent doped region between the channel 1 and the channel 2, as follows:

1 The control module controls the light source module to emit a detection pulse light signal, and the detection pulse light signal is injected into the optical channel of one end of the sensing fiber through the coupler;

2 The detecting pulse optical signal is transmitted from one end of the sensing fiber to the other end in the optical channel, and is acquired by the optical detecting module disposed at the other end of the sensing fiber, and the optical detecting module converts the pulsed optical signal into an electrical signal. Passed to the processing module;

3 When a certain part of the sensing fiber is changed by the physical quantity to be measured, the detecting light signal transmitted in the optical channel is partially coupled into the fluorescent cladding region between the optical channel 1 and the optical channel 2, and a large amount is excited. The fluorescent signal is partially coupled into the optical channel 2 and transmitted in the optical channel 2. Since the optical signal transmits at different speeds in the optical channel 1 and the optical channel 2, the detecting optical signal and the light transmitted in the optical channel are transmitted. The fluorescent signal transmitted in the channel 2 reaches the other end of the sensing fiber in sequence and is acquired by the optical detecting module. The optical detecting module converts the acquired optical signal into an electrical signal and transmits it to the processing module, and the processing module according to the size of the electrical signal. And the time interval calculates the size and location of the physical quantity to be measured, thereby completing the purpose of distributed monitoring.

3 When the detecting pulse light signal is transmitted in the optical channel, part of the detecting light signal is transmitted in the fluorescent cladding region, and the fluorescent signal is excited, and part of the fluorescent signal is coupled into the optical channel 2 and transmitted to the sensing channel in the optical channel 2 The end of the optical fiber is obtained by the optical detecting module, and the optical detecting module converts the pulsed optical signal into an electrical signal and transmits the signal to the processing module;

4 When a certain part of the sensing fiber is changed by the physical quantity to be measured, the fluorescent signal excited by the detecting optical signal also changes, and some of the fluorescent signals that are changed are coupled into the optical channel 2 and are in the optical channel 2 Transmission, because the transmission speed of the optical signal in the optical channel 1 and the optical channel 2 is different, the detection optical signal transmitted in the optical channel and the fluorescent signal transmitted in the optical channel 2 and the changed fluorescent signal are sequentially sequenced to reach the sensing fiber. One end is acquired by the optical detecting module, and the optical detecting module converts the acquired optical signal into an electrical signal and transmits it to the processing module, and the processing module calculates the size and position of the physical quantity to be measured according to the size and time interval of the electrical signal, thereby completing The purpose of distributed monitoring.

Beneficial effect

Compared with the prior art, the invention has the following advantages:

1 Through forward monitoring technology, the optical signal can be transmitted at a long distance, meeting the actual needs of natural gas pipelines and petroleum pipelines. Compared with the current Brillouin scattering monitoring device on the market, it has the characteristics of low cost, long monitoring distance and high precision. Has a good market prospects.

2 Because the dual channels in the sensing fiber and the speed of the optical signals transmitted in the two channels are different, one of the channels transmits the detecting pulse optical signal, and the other channel does not inject the optical signal. When the sensing fiber changes in one place, In the case of microbending, bending, deformation, etc., the injected optical signal escapes and is partially coupled into the channel near the uninjected optical signal, thereby being captured by the photodetector at the end of the sensing fiber due to the optical signals in the two channels. The difference between the transmission speed and the detection pulse optical signal and the optical signal in the other channel containing the physical quantity to be measured arrives at the photodetector in sequence, thereby distinguishing the size and time interval of different optical signals according to the physical quantity containing the physical quantity to be tested. The size of the optical signal can know the magnitude of the physical quantity to be measured. According to the interval between the detection pulse optical signal and the optical signal containing the physical quantity to be measured, the position of the physical quantity to be measured can be calculated, thereby completing the purpose of distributed monitoring. When there are multiple changes on the sensing fiber, a sequence of multiple pulsed optical signals is formed.

3 Since the effective area of the cladding 2 of the W-type fiber is much larger than the effective area of the core, a high-power pulsed light signal can be injected into the cladding 2, thereby increasing the length of the monitoring.

4 Since the device only injects an optical signal into one optical channel in the sensing fiber and detects the optical signal of the other optical channel, the dark field monitoring technology has high precision and accuracy.

In summary, the present invention is based on dual channels The distributed optical sensing device of optical fiber has the advantages of simple structure, low cost, long monitoring distance, and can realize distributed monitoring and sensing, and has a good market prospect.

DRAWINGS

The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments.

附图说明 DRAWINGS

FIG. 1 is a schematic structural view of Embodiment 1 of the present invention.

2 is a schematic structural view of a cross section of the sensing fiber of FIG. 1.

3 is a schematic structural view of a refractive index distribution in the radial direction of the sensing fiber of FIG. 2.

4 is a schematic structural view of a cross section of a sensing fiber according to Embodiment 2 of the present invention.

FIG. 5 is a schematic structural view of a refractive index distribution in the radial direction of the sensing fiber of FIG. 4. FIG.

FIG. 6 is a schematic structural view of Embodiment 3 of the present invention.

FIG. 7 is a schematic structural view of Embodiment 4 of the present invention.

Description of the reference signs:

1 - core; 2 - clad one; 3 - clad two; 4 - clad three; 5 - protective layer;

6 - processing module; 7 - photodetector module one; 8 - photodetector module two;

9 - coupler 2; 10 - control module; 11 - sensing fiber; 12 - light source module;

13 - coupler one; 14-output module; 15 - optical channel one; 16 - optical channel two;

17 - photodetector module three; 18-1 x 2 optical coupler; 19 - auxiliary fiber; 20-communication fiber;

21 - Core one; 22 - Core two; 23 - Inner cladding; 2 4 - Outer layer; 2 5 - Coating layer;

33 - transceiver module one; 34 - transceiver module two.

BEST MODE FOR CARRYING OUT THE INVENTION

具体实施方式 detailed description

实施例1 Example 1

Dual-channel distributed optical fiber sensing device as shown in FIG. 1, FIG. 2 and FIG. The control module 10, the light source module 12, the coupler one 13, the photodetector module 7 and the processing module 6, the control module 10 is connected to the light source module 12 and controls the latter to emit a pulsed light signal, and the light source module 12 passes through the auxiliary optical fiber 19. The coupler 13 is connected to one end of the sensing fiber 11. The sensing fiber 11 is an optical fiber including an optical channel 15 and an optical channel 26, and the coupler 1 13 is a coupler that couples the optical signal into only one of the optical channels within the sensing fiber 11, the speed of the optical signal of the same wavelength being transmitted within the optical channel 15 and the optical channel 26 is different; The other end of the sensing fiber 11 is connected to the photodetector 7 , and the photodetector 7 simultaneously acquires the optical signals transmitted in the optical channel 15 and the optical channel 26, and the photodetector 7 is connected to the processing module 6. Preferably, the processing module 6 is connected to the output module 14.

1 The control module 10 controls the light source module 12 to emit a pulsed light signal, and the pulsed light signal is injected into the optical channel 15 at one end of the sensing fiber 11 through the coupler 13;

2 The pulsed light signal is transmitted from one end of the sensing fiber 11 to the other end in the optical channel 15, and is received by the light detecting module 7 at the other end of the sensing fiber 11, and the light detecting module 7 applies the pulsed optical signal. Converted into an electrical signal to the processing module 6;

3 When somewhere on the sensing fiber 11 is changed by the physical quantity to be measured, the optical signal transmitted in the optical channel 15 is partially coupled into the optical channel 26 and transmitted in the optical channel 26 due to the optical channel. When the transmission speeds of the optical signals having the same wavelength in the optical channel and the optical channel 26 are different, the optical signals in the optical channel 15 and the optical channel 26 are sequentially passed to the other end of the sensing fiber 11 and are acquired by the optical detecting module 7 for optical detection. The module 7 converts the acquired optical signal into an electrical signal and transmits it to the processing module 6. The processing module 6 calculates the size and position of the physical quantity to be measured according to the size and time interval of the electrical signal, thereby completing the purpose of distributed monitoring.

The photodetector 7 , the photodetector 2 , and the photodetecting module 3 17 may be one of an optical power meter, a photon counter, a spectrum analyzer, and a wavelength meter.

The light source module 12 can be one of a single wavelength light source, a multi-wavelength light source, or a broadband light source. For example, a single-wavelength light source is a DFB laser, and its output optical signal has a stable wavelength and a large power. The multi-wavelength source can be constructed from a plurality of DFB lasers.

When the photodetector 7 , the photodetector 2 , and the photodetecting module 3 17 are optical power meter and photon counter testing instruments, preferably, the light source module 12 can be one of a single wavelength source and a multi-wavelength source. The detector of the device of the invention collects the power of the pulsed optical signal, and can calculate the magnitude of the physical quantity to be tested according to the power level; when the photodetector-7, the photodetector 2, and the optical detection module 317 are used Preferably, the light source module 12 can be one of a multi-wavelength light source or a broadband light source. The device of the present invention collects the wavelength information of the pulsed light signal, and can calculate the measured value according to the information. The size of the physical quantity.

The sensing fiber 11 is a W-type fiber, which is radially distributed from the center to the edge, and includes a core 1, a cladding layer 2, a cladding layer 2, and a cladding layer 3, which are in turn. The refractive index is greater than the refractive index of the cladding layer 2, and the refractive index of the cladding layer 3 is greater than the refractive index of the cladding layer 2 and the cladding layer 4, and the protective layer 5 is outside the cladding layer 3; the core 1 and The cladding 2 is the optical channel 15 and the optical channel 26 of the sensing fiber 11, respectively.

Preferably, the core 1 and the cladding 2 of the sensing fiber 11 are quartz glass doped with germanium and boron.

Preferably, the cladding layer 2 of the sensing fiber 11 is a quartz glass doped with fluorine.

Preferably, the cladding layer 3 of the sensing fiber 11 is a high-purity quartz glass.

Preferably, the core 1 of the sensing fiber 11 has a refractive index higher than that of the cladding layer 2 by 0.3%.

Preferably, the refractive index of the cladding layer 3 of the sensing fiber 11 is 0.1% higher than the refractive index of the cladding layer 2, and the refractive index of the cladding layer 3 is higher than that of the cladding layer 3 Out of 0.3%.

Preferably, at least the region between the light channel 15- and the light channel 26 is a fluorescent cladding region, and the fluorescent cladding region is composed of a transparent material doped with a fluorescent material. The method of operation, the steps are as follows:

1 The control module 10 controls the light source module 12 to emit a probe pulse light signal, and the probe pulse light signal is injected into the optical channel 15 at one end of the sensing fiber 11 through the coupler 3;

2 The detecting pulse light signal is transmitted from one end of the sensing fiber 11 to the other end in the optical channel 15, and is acquired by the light detecting module 7 at the other end of the sensing fiber 11, and the light detecting module 7 applies the pulsed light. The signal is converted into an electrical signal and transmitted to the processing module 6; the optical detecting module 7 can be one of an optical power meter, a photon counter, a spectrum analyzer, and a wavelength meter;

3 When a certain portion of the sensing fiber 11 is changed by the physical quantity to be measured, the detecting light signal transmitted in the optical channel 15 is partially coupled into the fluorescent cladding region between the optical channel 15 and the optical channel 26, And a large number of fluorescent signals are excited, and some fluorescent signals are coupled into the optical channel 26 and transmitted in the optical channel 26, since the optical signal transmits speeds in the optical channel 15 and the optical channel 26, the optical channel is different. The probe optical signal transmitted in the 15 and the fluorescent signal transmitted in the optical channel 26 are sequentially passed to the other end of the sensing fiber 11 and are acquired by the optical detecting module-7. The optical detecting module 7 converts the acquired optical signal into electricity. The signal is transmitted to the processing module 6. The processing module 6 calculates the size and position of the physical quantity to be measured according to the size and time interval of the electrical signal, thereby completing the purpose of distributed monitoring.

Another method of operation when the sensing fiber 11 has a fluorescent doped region between channel one 15 and optical channel two 16 is as follows:

1 The control module 10 controls the light source module 12 to emit a probe pulse light signal, and the probe pulse light signal is injected into the optical channel 15 at one end of the sensing fiber 11 through the coupler 13;

2 The detecting pulse light signal is transmitted from one end of the sensing fiber 11 to the other end in the optical channel 15, and is acquired by the light detecting module 7 at the other end of the sensing fiber 11, and the light detecting module 7 applies the pulsed light. Signal is converted into an electrical signal to the processing module 6;

3 When the detecting pulse light signal is transmitted in the optical channel 15, a part of the detecting light signal is transmitted in the fluorescent cladding region, and the fluorescent signal is excited, and part of the fluorescent signal is coupled into the optical channel 26 and transmitted in the optical channel 26 To the end of the sensing fiber 11 and is captured by the light detecting module-7, the light detecting module 7 converts the pulsed optical signal into an electrical signal to the processing module 6;

4 When a certain portion of the sensing fiber 11 is changed by the physical quantity to be measured, the fluorescent signal excited by the detecting optical signal also changes, and a part of the fluorescent signal that is changed is coupled into the optical channel 26 and in the optical channel. In the transmission within the two 16th, since the transmission speed of the optical signal in the optical channel 15 and the optical channel 26 is different, the detection optical signal transmitted in the optical channel 15 and the fluorescent signal transmitted in the optical channel 26 and the fluorescent signal are changed. The sequence reaches the other end of the sensing fiber 11 and is acquired by the light detecting module-7. The light detecting module 7 converts the acquired optical signal into an electrical signal and transmits it to the processing module 6. The processing module 6 is based on the size and time interval of the electrical signal. Calculate the size and location of the physical quantity to be measured, thus completing the purpose of distributed monitoring.

Embodiments of the invention

Example 2

As shown in FIG. 4 and FIG. 5, this embodiment is different from Embodiment 1 in that: the sensing fiber 11 is a dual-core fiber. The inner cladding layer 23 and the outer cladding layer 24 located outside the inner cladding layer 23 are disposed with the core 21 and the core 22 in the inner cladding layer 23, and the refractive indices of the core 21 and the core 22 are greater than The refractive index of the inner cladding 23, the refractive index of the inner cladding 23 is greater than the refractive index of the outer cladding 24, and the outer layer 24 is a coating layer 25; the core 21 and the core 22 are respectively the sensing Optical path 15 and optical path 2 of optical fiber 11.

Preferably, the refractive index of the core 21 is higher than the refractive index of the core 22;

Preferably, the outer diameter of the core 21 is larger than the outer diameter of the core 22 .

Preferably, the core 21 and the core 22 are disposed in the inner cladding 23 in a spiral form.

Preferably, the core 21 is located on the central axis of the optical fiber, and the core 22 is spirally disposed around the core 21.

In this embodiment, the structure, connection relationship and working principle of the remaining portions are the same as those of the first embodiment.

Example 3

As shown in FIG. 6, this embodiment is different from Embodiment 1 in that: a dual-channel distributed optical fiber sensing device The control module 10, the light source module 12, the coupler 13 , the photodetector module 7 , the light detecting module 2 , the coupler 2 , and the processing module 6 , wherein the control module 10 is connected to the light source module 12 and controlled The light source module 12 is connected to the coupler 13 , and the coupler 13 is connected to one end of the sensing fiber 11 . The sensing fiber 11 includes an optical channel 15 and an optical channel 2 . The optical fiber, the coupler 13 is a coupler that couples the optical signal into only one of the optical channels of the sensing optical fiber 11, and the speed of the optical signal transmitted in the optical channel 15 and the optical channel 26 The other end of the sensing fiber 11 is connected to the coupler 2, and the coupler 9 includes a channel 1 and a channel 2, and the channel 1 and the channel 2 do not interfere with each other. The sensing fiber 11 The optical channel 15 is connected to the channel in the coupler 2, and the channel is connected to the photodetector 7; the optical channel 26 in the sensing fiber 11 and the channel 2 in the coupler 9 Connection, channel two and connected to photodetector 2; A photodetector unit 7 and the two 8 connected to the processing module 6.

2 The pulsed optical signal is transmitted from one end of the sensing fiber 11 to the other end in the optical channel 15, and the coupler 2 is disposed at the other end of the sensing fiber 11, and the channel 1 in the coupler 9 is connected to the optical channel 15. The other end of the channel is connected to the light detecting module-7, the channel 2 in the coupler 2 is connected to the optical channel 26, and the other end of the channel 2 is connected to the optical detecting module 2, the light detecting module 7 and the light detecting module 2 The pulsed optical signals transmitted in the optical channel 15 and the optical channel 26 are respectively converted into electrical signals and transmitted to the processing module 6;

3 When somewhere on the sensing fiber 11 is changed by the physical quantity to be measured, the optical signal transmitted in the optical channel 15 is partially coupled into the optical channel 26 and transmitted in the optical channel 26 due to the optical channel. The optical signals of the optical channel 15 and the optical channel 26 are different in sequence, and the optical signals in the optical channel 15 and the optical channel 26 are sequentially received at the other end of the sensing fiber 11 and are respectively obtained by the optical detecting module 7 and the optical detecting module 2 The optical detecting module 7 and the optical detecting module 2 respectively convert the acquired optical signals into electrical signals and transmit them to the processing module 6. The processing module 6 calculates the magnitude of the physical quantity to be measured according to the order, size and time interval of the electrical signals. Location, thus completing the purpose of distributed monitoring.

Example 4

As shown in FIG. 7, this embodiment is different from Embodiment 3 in that it further includes a 1×2 optical coupler 18 disposed between the light source module 12 and the coupler 13 , and the light source module 12 and the 1×2 optical coupler 18 . One port end connection, one end of the two ports of the 1×2 optical coupler 18 is connected to the coupler 13 , and one end of the two ports of the 1×2 optical coupler 18 is connected to the light detecting module three 17 , and the light detecting module three 17 Connected to the control module 10.

Operational steps, including A 1×2 optical coupler 18 disposed between the light source module 12 and the coupler 13 is connected to the 1-port end of the 1×2 optical coupler 18, and the 2-port end of the 1×2 optical coupler 18 Connected to the coupler 13 , one end of the two ports of the 1×2 optical coupler 18 is connected to the light detecting module three 17 , and the light detecting module three 17 is connected to the control module 10 ; the pulsed light signal emitted by the light source module 12 passes through 1× After the optocoupler 18, a small portion of the optical coupler 18 enters the light detecting module 3, and the optical detecting module 3 17 converts the signal into an electrical signal and transmits the signal to the control module 10. The control module 10 calculates the pulsed light emitted by the light source module 12 according to the electrical signal. The intensity of the signal is converted into a previously set code, and the control module 10 controls the light source module 12 to emit the code; the light detecting module 7 acquires the optical signal containing the code and converts it into an electrical signal and transmits the signal to the processing module. 6. The processing module 6 compares the code with the preset encoding table, obtains the size of the pulsed light signal emitted by the light source module 12, and corrects the size and position of the physical quantity to be measured according to the value.

Preferably, the communication fiber 20 is disposed in parallel with the sensing fiber 11. The two ends of the communication fiber 20 are respectively connected to the transceiver module 33 and the transceiver module 34, and the transceiver module 33 and the transceiver module 34 are respectively connected to the control module 10. It is connected to the processing module 6.

Its running steps, A 1×2 optical coupler 18 disposed between the light source module 12 and the coupler 13 is further included. The light source module 12 is connected to the 1-port end of the 1×2 optical coupler 18, and the 2-port of the 1×2 optical coupler 18 One end of the 1×2 optical coupler 18 is connected to the light detecting module 3 17 , and the light detecting module 3 17 is connected to the control module 10; the pulsed light signal emitted by the light source module 12 passes. After the 1×2 optical coupler 18, a small portion enters the light detecting module 317, and the light detecting module 317 converts the signal into an electrical signal and transmits the signal to the control module 10. The control module 10 calculates the light source module 12 according to the electrical signal. The size of the pulsed optical signal is converted into a preset code, and the control module 10 controls the transceiver module 33 to send the code through the communication fiber 20; the transceiver module 34 obtains the encoded optical signal through the communication fiber 20 and converts it. The electrical signal is transmitted to the processing module 6, and the processing module 6 compares the size of the pulsed light signal emitted by the light source module 12, such as the power level or the wavelength state of the pulsed light signal, according to the encoding and the preset encoding table, and according to the value Correct the size and position of the physical quantity to be measured.

Preferably, the 1×2 optical coupler 18 is an optical splitter with a 1:99 optical signal distribution ratio, wherein one end of the optical signal distribution is connected to the coupler 13 and the end of the optical signal is distributed and the light is detected. Module three 17 is connected.

In this embodiment, the structure, connection relationship and working principle of the remaining portions are the same as those of the third embodiment.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any simple modifications, changes, and equivalent structural changes made to the above embodiments in accordance with the technical spirit of the present invention still belong to the present technology. Within the scope of protection of the program.

Industrial applicability

Sequence table free content

Claims

Dual-channel distributed optical fiber sensing device The utility model is characterized in that it comprises a control module (10), a light source module (12), a coupler one (13), a photodetector module one (7) and a processing module (6), a control module (10) and a light source module (12). Connecting and controlling the latter to emit a pulsed light signal, the light source module (12) is coupled to the coupler (13), and the coupler (13) is coupled to one end of the sensing fiber (11), the sensing The optical fiber (11) is an optical fiber including a light channel one (15) and a light channel two (16), and the coupler one (13) is one of the optical channels for coupling the optical signal into the sensing fiber (11). In the inner coupler, the optical signals of the same wavelength are transmitted at different speeds in the optical channel (15) and the optical channel two (16); at the other end of the sensing fiber (11) and the photodetector One (7) connection, photodetector one (7) is connected to the processing module (6).
Dual-channel based distributed optical fiber sensing device according to claim The one end of the sensing fiber (11) is connected to the coupler (9), and the coupler (9) includes a channel one and a channel two, and the channel one and the channel two do not interfere with each other. The optical channel (15) in the sensing fiber (11) is connected to the channel in the coupler (9), and the channel is connected to the photodetector (7); the sensing fiber (11) The optical channel 2 (16) is connected to the channel 2 in the coupler 2 (9), the channel 2 is connected to the photodetector 2 (8); the photodetector 1 (7) and the photodetector 2 (8) are The processing module (6) is connected.
Dual-channel distributed optical fiber sensing device according to claim 1 or 2 It is characterized in that: a 1×2 optical coupler (18) disposed between the light source module (12) and the coupler (13), and a light source module (12) and a 1×2 optical coupler (18) End connection, one end of the two ports of the 1×2 optical coupler (18) is connected to the coupler one (13), and one end of the two ports of the 1×2 optical coupler (18) is connected to the light detecting module three (17). The light detecting module three (17) is connected to the control module (10).
Dual-channel based distributed optical fiber sensing device according to claim The 1×2 optical coupler (18) is an optical splitter with a 1:99 optical signal distribution ratio, wherein one end of the optical signal distribution is connected to the coupler (13) to distribute the optical signal. The lesser end is connected to the light detecting module three (17).
Dual-channel distributed optical fiber sensing device according to claim 1, 2, 3 or 4 The utility model further comprises: a communication optical fiber (20) disposed in parallel with the sensing optical fiber (11), wherein two ends of the communication optical fiber (20) are respectively connected to the transceiver module (33) and the transceiver module (34), and the transceiver module (33) and the transceiver module two (34) are in turn connected to the control module (10) and the processing module (6).
Dual-channel distributed optical fiber sensing device according to claim 1 or 2 The invention is characterized in that: the photodetector one (7), the photodetector two (8), and the light detecting module three (17) are one of an optical power meter, a photon counter, a spectrum analyzer, and a wavelength meter.
Dual-channel distributed optical fiber sensing device according to claim 1 or 2 The light source module (12) is one of a single wavelength light source, a multi-wavelength light source or a broadband light source.
Dual-channel distributed optical fiber sensing device according to claim 1 or 2 The sensing fiber (11) is a W-type fiber, which is radially distributed from the center to the edge, and includes a core (1), a cladding layer (2), and a cladding layer (3). And the cladding layer (4), the refractive index of the core (1) is greater than the refractive index of the cladding layer (2), and the refractive index of the cladding layer (3) is greater than that of the cladding layer (2) and the cladding layer The refractive index of (4) is a protective layer (5) outside the cladding layer (4); the core (1) and the cladding layer (3) are optical channels of the sensing fiber (11), respectively One (15) and two optical channels (16).
The dual-channel distributed optical fiber sensing device according to claim 1 or 2, wherein: said sensing fiber (11) is a dual-core fiber , comprising an inner cladding layer (23) and an outer cladding layer (24) located outside the inner cladding layer (23), and a core one (21) and a core core (22) are arranged side by side in the inner cladding layer (23), the fiber The refractive index of the core one (21) and the core two (22) is larger than the refractive index of the inner cladding layer (23), and the refractive index of the inner cladding layer (23) is larger than the refractive index of the outer cladding layer (24), outside the outer cladding layer (24) It is a coating layer (25); the core one (21) and the core two (22) are the optical channel one (15) and the optical channel two (16) of the sensing fiber (11), respectively.
Dual-channel distributed optical fiber sensing device according to claim 1 or 2 It is characterized in that at least the region between the light channel one (15) and the light channel two (16) is a fluorescent cladding region, and the fluorescent cladding region is composed of a transparent material doped with a fluorescent material.
A method for operating a distributed optical fiber sensing device based on two channels, characterized in that the steps are as follows:

1 The control module (10) controls the light source module (12) to emit a pulsed light signal, and the pulsed light signal is injected into the optical channel (15) at one end of the sensing fiber (11) through the coupler (13);

2 The pulsed light signal is transmitted from one end of the sensing fiber (11) to the other end in the optical channel (15), and is received by the light detecting module (7) disposed at the other end of the sensing fiber (11), and the light is detected. Module one (7) converts the pulsed optical signal into an electrical signal and transmits it to the processing module (6);

3 When the sensing fiber (11) is changed by the physical quantity to be measured, the optical signal transmitted in the optical channel (15) is partially coupled into the optical channel 2 (16) and in the optical channel 2 ( 16) In the inner transmission, since the transmission speeds of the optical signals in the optical channel one (15) and the optical channel two (16) are different, the optical signals in the optical channel one (15) and the optical channel two (16) are sequentially passed to the sensing fiber ( 11) The other end is obtained by the light detecting module (7), and the light detecting module (7) converts the acquired optical signal into an electrical signal and transmits it to the processing module (6), and the processing module (6) according to the size of the electrical signal And the time interval calculates the size and location of the physical quantity to be measured, thereby completing the purpose of distributed monitoring.
A method for operating a distributed optical fiber sensing device based on two channels, characterized in that the steps are as follows:

1 The control module (10) controls the light source module (12) to emit a pulsed light signal, and the pulsed light signal is injected into the optical channel (15) at one end of the sensing fiber (11) through the coupler (13);

2 The pulsed optical signal is transmitted from one end of the sensing fiber (11) to the other end in the optical channel (15), and the coupler (9) is disposed at the other end of the sensing fiber (11), and the coupler (9) The inner channel is connected to the optical channel one (15), the other end of the channel is connected to the light detecting module (7), the channel two in the coupler two (9) is connected to the optical channel two (16), and the other end of the channel two is connected. Connected to the light detecting module 2 (8), the light detecting module 1 (7) and the light detecting module 2 (8) respectively convert the pulsed light signals transmitted in the optical channel (15) and the optical channel 2 (16) into electrical signals and Passed to the processing module (6);

3 When the sensing fiber (11) is changed by the physical quantity to be measured, the optical signal transmitted in the optical channel (15) is partially coupled into the optical channel 2 (16) and in the optical channel 2 ( 16) In the inner transmission, since the transmission speeds of the optical signals in the optical channel one (15) and the optical channel two (16) are different, the optical signals in the optical channel one (15) and the optical channel two (16) are sequentially passed to the sensing fiber ( 11) The other end is respectively obtained by the light detecting module one (7) and the light detecting module two (8), and the light detecting module one (7) and the light detecting module two (8) respectively convert the acquired optical signal into an electrical signal and transmit To the processing module (6), the processing module (6) calculates the size and position of the physical quantity to be measured according to the order, size and time interval of the electrical signal, thereby completing the purpose of distributed monitoring.
The method for operating a dual-channel distributed optical fiber sensing device according to claim 12, wherein: in step 3) Also included is a 1×2 optical coupler (18) disposed between the light source module (12) and the coupler one (13), and the light source module (12) is connected to the 1-port end of the 1×2 optical coupler (18). One end of the two ports of the 1×2 optical coupler (18) is connected to the coupler one (13), and one end of the two ports of the 1×2 optical coupler (18) is connected to the light detecting module three (17), and the light detecting module The third (17) is connected to the control module (10); the pulsed light signal emitted by the light source module (12) passes through the 1×2 optical coupler (18) and a small portion enters the light detecting module three (17), and the light detecting module three (17) converting the signal into an electrical signal to the control module (10), and the control module (10) calculates the magnitude of the pulsed light signal emitted by the light source module (12) based on the electrical signal and converts the value into a preset Encoding, the control module (10) controls the light source module (12) to emit the code; the light detecting module 2 (8) acquires the optical signal containing the code and converts it into an electrical signal and transmits it to the processing module (6), the processing module ( 6) According to the encoding and the preset coding table, the light source module is obtained (12) The size of the pulsed light signal is emitted, and the magnitude and position of the physical quantity to be measured are calculated according to the value.
The method for operating a dual-channel distributed optical fiber sensing device according to claim 12, wherein: in step 3) Also included is a 1×2 optical coupler (18) disposed between the light source module (12) and the coupler one (13), and the light source module (12) is connected to the 1-port end of the 1×2 optical coupler (18). One end of the two ports of the 1×2 optical coupler (18) is connected to the coupler one (13), and one end of the two ports of the 1×2 optical coupler (18) is connected to the light detecting module three (17), and the light detecting module The third (17) is connected to the control module (10); the pulsed light signal emitted by the light source module (12) passes through the 1×2 optical coupler (18) and a small portion enters the light detecting module three (17), and the light detecting module three (17) converting the signal into an electrical signal to the control module (10), and the control module (10) calculates the magnitude of the pulsed light signal emitted by the light source module (12) based on the electrical signal and converts the value into a preset The coding, control module (10) controls the transceiver module (33) to transmit the code through the communication fiber (20); the transceiver module (34) obtains the encoded optical signal through the communication fiber (20) and converts it into an electrical signal transmission. To the processing module (6), the processing module (6) according to the encoding and pre- The coding table is compared to obtain the size of the pulse light signal emitted by the light source module (12), and the magnitude and position of the physical quantity to be measured are calculated according to the value.
A method for operating a distributed optical fiber sensing device based on two channels, characterized in that the steps are as follows:

1 The control module 10) controls the light source module (12) to emit a probe pulse light signal, and the probe pulse light signal is injected into the optical channel one (15) of one end of the sensing fiber (11) through the coupler (3);

2 The detecting pulse light signal is transmitted from one end of the sensing fiber (11) to the other end in the optical channel (15), and is received by the light detecting module (7) disposed at the other end of the sensing fiber (11). The detecting module (7) converts the pulsed optical signal into an electrical signal and transmits it to the processing module (6);

3 When the sensing fiber 11) is changed by the physical quantity to be measured, the detecting light signal transmitted in the optical channel (15) is partially coupled into the optical channel one (15) and the optical channel two (16). The fluorescent cladding region and a large amount of fluorescent signal are excited, and part of the fluorescent signal is coupled into the optical channel 2 (16) and transmitted in the optical channel 2 (16), since the optical signal is in the optical channel (15) and the optical channel The transmission speeds of the optical signals in the two (16) are different, and the probe light signals transmitted in the optical channel (15) and the fluorescent signals transmitted in the optical channel two (16) are sequentially passed to the other end of the sensing fiber (11) and are The light detecting module (7) acquires, the light detecting module (7) converts the acquired optical signal into an electrical signal and transmits it to the processing module (6), and the processing module (6) calculates the waiting according to the size and time interval of the electrical signal. The size and location of physical quantities are measured to accomplish the purpose of distributed monitoring.
A method for operating a distributed optical fiber sensing device based on two channels, characterized in that the steps are as follows:

1 The control module (10) controls the light source module (12) to emit a probe pulse light signal, and the probe pulse light signal is injected into the optical channel (15) at one end of the sensing fiber (11) through the coupler (13);

2 The detecting pulse light signal is transmitted from one end of the sensing fiber (11) to the other end in the optical channel (15), and is received by the light detecting module (7) disposed at the other end of the sensing fiber (11). The detecting module (7) converts the pulsed optical signal into an electrical signal and transmits it to the processing module (6);

3 When the detecting pulse light signal is transmitted in the optical channel (15), a part of the detecting light signal is transmitted in the fluorescent cladding region, and a fluorescent signal is excited, and a part of the fluorescent signal is coupled into the optical channel 2 (16) and in the optical channel. The second (16) is transmitted to the end of the sensing fiber (11) and is obtained by the light detecting module (7). The light detecting module (7) converts the pulsed optical signal into an electrical signal and transmits it to the processing module (6). );

4 When a certain part of the sensing fiber (11) is changed by the physical quantity to be measured, the fluorescent signal excited by the detecting light signal also changes, and some of the fluorescent signals that are changed are coupled into the optical channel 2 (16). And transmitting in the optical channel two (16), since the transmission speed of the optical signal in the optical channel one (15) and the optical channel two (16) is different, the detecting light signal and the optical channel two transmitted in the optical channel one (15) 16) The internally transmitted fluorescent signal and the changed fluorescent signal arrive at the other end of the sensing fiber (11) in sequence and are acquired by the light detecting module (7), and the light detecting module (7) converts the acquired optical signal into The electrical signal is transmitted to the processing module (6), and the processing module (6) calculates the size and position of the physical quantity to be measured according to the size and time interval of the electrical signal, thereby completing the purpose of distributed monitoring.