CN103344264A - Multichannel optical fiber sensing network demodulating system - Google Patents

Abstract

A multichannel optical fiber sensing network demodulating system comprises a pump light source. The input end of an optical wavelength division multiplexer is connected with the output end of the pump light source, the input end of an opto-isolator is connected with the first output end of the wavelength division multiplexer, the first input end of a michelson interferometer is connected with the output end of the opto-isolator, the input end of an optical dense wavelength division multiplexer is connected with the output end of the michelson interferometer, the input end of a photoelectric detector array is connected with the output end of the optical dense wavelength division multiplexer, the first input end of a data acquisition card is connected with the output end of a photoelectric detector, the first output end of a carrier circuit is connected with the second input end of the michelson interferometer, the second output end of the carrier circuit is connected with the second input end of the data acquisition card, the input end of a data processing module is connected with the output end of the data acquisition card, and the input end of a fiber laser type sensor array is connected with the second output end of the wavelength division multiplexer. The multichannel optical fiber sensing network demodulating system can solve the technical problem of real-time demodulation of short development cycle and low cost with enlargement of the range of a sensing network of an optical fiber sensing network.

Description

Multi-channel fiber optic sensor network demodulation system

technical field

The invention belongs to the field of optical fiber sensing and optical signal processing, and more specifically relates to a multi-channel high-precision network signal demodulation system based on optical fiber sensing.

Background technique

Compared with traditional mechanical and electrical sensing, fiber optic sensing has many excellent properties, such as: high sensitivity, large dynamic range, anti-electromagnetic interference, anti-corrosion, small size, light weight, easy to reuse, etc., which makes the sensor The technology has broad application prospects in harsh environments such as underground and high-sensitivity sensing (such as microseismic monitoring, safety monitoring, etc.). With the development of optical fiber sensing technology, the single-point optical fiber sensing system is far from meeting the requirements. The point fiber sensor network has been proposed one after another. With the development of the sensor network, the analysis and processing of the network signal has been paid more and more attention and developed. In recent years, it has been proposed to mix the above multiplexing technologies to increase the multiplexing scale of the optical fiber sensor network. In the above background, the multi-point sensing network and its demodulation system applied in the field of optical fiber sensing have attracted extensive attention. In this type of system, issues such as power balance and phase consistency of each sensor, and network signal pickup and identification must be resolved. At this time, the demodulation system must optimize the design of the system hardware, optimize the design of key software parameters and improve the demodulation algorithm as much as possible under the premise of completing the collection of signals to make the system's noise level, dynamic range, stability, repeatability, Correlation, consistency, crosstalk and other performances are optimized as much as possible to meet and exceed the current requirements in the field of optical fiber sensing. Furthermore, a general-purpose optical fiber sensor network demodulation system should also be implemented to improve system compatibility and reduce network deployment and maintenance costs. Up to now, the prior art cannot well meet the above requirements.

To sum up, in order to solve the above-mentioned technical bottlenecks and build a high-performance, high-stability, real-time, and highly compatible optical fiber sensor network demodulation system, there is an urgent need for a multi-channel high-precision fiber optic sensor network solution. Tune the system.

Contents of the invention

The purpose of the present invention is to provide a multi-channel optical fiber sensor network demodulation system, which can solve the problem of low development cycle, low cost, high performance, high stability and real-time Demodulation technical issues.

The present invention provides a multi-channel optical fiber sensor network demodulation system, comprising:

pump light source;

An optical wavelength division multiplexer, the input end of which is connected to the output end of the pumping light source;

An optical isolator, its input end is connected with the first output end of the wavelength division multiplexer;

Michelson interferometer, its first input end is connected with the output end of optical isolator;

Optical dense wavelength division multiplexer, its input end is connected with the output end of Michelson interferometer;

A photodetector array, the input of which is connected to the output of the optical dense wavelength division multiplexer;

A data acquisition card, the first input end of which is connected to the output end of the photodetector;

A carrier circuit, the first output end of which is connected to the second input end of the Michelson interferometer, and the second output end is connected to the second input end of the data acquisition card;

Data processing module, its input end is connected with the output end of data acquisition card;

The fiber laser type sensor array, its input terminal is connected with the second output terminal of the wavelength division multiplexer.

As can be seen from the foregoing technical solutions, the present invention has the following beneficial effects:

The multi-channel high-precision optical fiber sensor network demodulation system has simple structure, low power consumption, low construction and maintenance costs, short development cycle, high demodulated wavelength shift resolution, and can complete multi-channel synchronous real-time demodulation.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings, wherein:

Fig. 1 is a structural representation of the present invention;

FIG. 2 is an embodiment of FIG. 1 , showing a schematic structural diagram of a demodulation system with a multi-channel optical fiber sensor network.

Detailed ways

Please refer to shown in Fig. 1, the present invention provides a kind of multi-channel optical fiber sensor network demodulation system, comprising:

The pumping light source a is used to provide pumping light to the fiber optic laser sensor array j to excite the fiber laser sensor to generate laser output, and the number of the pumping light source a is greater than or equal to 1;

The optical wavelength division multiplexer b, whose input end is connected to the output end of the pumping light source a, is used to transmit the output light of the pumping light source a to the fiber laser type sensor array j, and simultaneously receives the output light from the fiber laser type sensor array j Laser, the number of the optical wavelength division multiplexer b is greater than or equal to 1, and its multiplexing center wavelength is consistent with the wavelength range of the pump light source a and the fiber laser sensor array j;

An optical isolator c, whose input end is connected to the first output end of the wavelength division multiplexer b, is used to reduce the influence of backscattered light in the optical fiber on the system operation, and the number of the optical isolator c is greater than or equal to 1 :

Michelson interferometer d, its first input end is connected with the output end of optical isolator c, is used for converting the wavelength displacement signal of fiber laser type sensor array j into phase signal, produces interference fringe output simultaneously, described Michelson Interferometer d is a Mach-Zehnder interferometer with polarization control;

The optical dense wavelength division multiplexer e, whose input end is connected with the output end of the Michelson interferometer d, is used to separate the optical signal output by each fiber laser type sensor in the fiber laser type fiber sensor array j, and transmit them to Each photodetector in the photodetector array f;

A photodetector array f, whose input terminal is connected to the output terminal of the optical dense wavelength division multiplexer e, is used to convert the received optical signal into an analog electrical signal;

Data acquisition card g, its first input end is connected with the output end of photodetector f, is used for converting the analog electric signal that receives into digital electric signal;

Carrier circuit h, its first output terminal is connected to the second input terminal of Michelson interferometer d, and the second output terminal is connected to the second input terminal of data acquisition card g, which is used to load and modulate the PZT inside the Michelson interferometer signal, and provide a carrier signal to the data acquisition card g so that the data processing module i performs data processing, and the carrier circuit h is a signal generator;

Data processing module i, its input end is connected with the output end of data acquisition card g, is used to receive the digital electric signal of data acquisition card g output and completes the analysis, processing of signal, and described data processing system i is DSP module, FPGA module or PC module;

The fiber laser sensor array j, its input terminal is connected to the second output terminal of the wavelength division multiplexer b, and the center wavelength of the fiber laser sensor array j is located within the channel range of the optical dense wavelength division multiplexer e .

Please refer to shown in Fig. 2, show the structure schematic diagram with multi-channel optical fiber sensing network demodulation system, wherein

There are four pump light sources a;

There are four optical wavelength division multiplexers b, and the input end of each optical wavelength division multiplexer is respectively connected to the output end of a pumping light source a;

There are four optical isolators c, and each input end is connected to the first output end of an optical wavelength division multiplexer b;

Described Michelson interferometer d, each first input end of it is respectively connected with the output end of an optical isolator c;

There are four optical dense wavelength division multiplexers e, each of which is connected to an output of the Michelson interferometer d;

Described photodetector array f, its input end is respectively connected with an output end of optical dense wavelength division multiplexer e;

Described data acquisition card g, its first input end is connected with the output end of photodetector f;

Described carrier circuit h, its first output end is connected with the second input end of Michelson interferometer d, and the second output end is connected with the second input end of data acquisition card g;

Described data processing module i, its input end is connected with the output end of data acquisition card g;

The input end of the fiber laser sensor array j is connected to the second output end of the wavelength division multiplexer b.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (7)

1. multichannel optical fiber sensing network demodulation system comprises:

Pump light source;

Light wavelength division multiplexing, its input end is connected with the output terminal of pump light source;

Optoisolator, its input end is connected with first output terminal of wavelength division multiplexer;

Michelson interferometer, its first input end is connected with the output terminal of optoisolator;

The light dense wave division multiplexer, its input end is connected with the output terminal of Michelson interferometer;

Photodetector array, its input end is connected with the output terminal of light dense wave division multiplexer;

Data collecting card, its first input end is connected with the output terminal of photodetector;

Carrier current channel, its first output terminal is connected with second input end of Michelson interferometer, and second output terminal is connected with second input end of data collecting card;

Data processing module, its input end is connected with the output terminal of data collecting card;

Optical-fiber laser type sensor array, its input end is connected with second output terminal of wavelength division multiplexer.

2. multichannel optical fiber sensing network demodulation according to claim 1 system, wherein the quantity of pump light source, light wavelength division multiplexing, optoisolator and light dense wave division multiplexer is more than or equal to 1.

3. multichannel optical fiber sensing network demodulation according to claim 1 system, wherein the wavelength of each passage of light wavelength division multiplexing is consistent with the wavelength scope of living in of optical-fiber laser type sensor.

4. multichannel optical fiber sensing network demodulation according to claim 1 system, wherein carrier current channel is signal generator.

5. multichannel optical fiber sensing network demodulation according to claim 1 system, wherein the centre wavelength of optical-fiber laser type sensor is positioned within the wavelength coverage of each passage of light dense wave division multiplexer.

6. multichannel optical fiber sensing network demodulation according to claim 1 system, data processing module wherein is DSP module, FPGA module or PC module.

7. multichannel optical fiber sensing network demodulation according to claim 1 system, wherein Michelson interferometer is the Mach-Zehnder interferometer of band Polarization Control.

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