Optical Fiber Bragg Grating Sensing System and Operation Method Based on Narrowband Scanning Light Source

A fiber grating and sensing system technology, applied in the direction of using optical devices, thermometers with physical/chemical changes, measuring devices, etc., can solve the problems of poor signal-to-noise ratio of sensing signals, low utilization of light sources, and problems that can be demodulated Problems such as the number of sensors and demodulation accuracy, to achieve high signal-to-noise ratio, improve demodulation speed, and improve scanning speed

Active Publication Date: 2016-04-13
NO 34 RES INST OF CHINA ELECTRONICS TECH GRP
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Since only a small part of the broadband light source is used at each moment in the existing fiber grating sensing system, the utilization rate of the light source is low, and the signal-to-noise ratio of the sensing signal is poor.
And because the backend can only scan one channel each time it scans the frequency, it is difficult to realize the multiplexing of fiber grating sensors and real-time wavelength calibration, which directly affects the number of sensors that can be demodulated and the demodulation accuracy

Method used

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  • Optical Fiber Bragg Grating Sensing System and Operation Method Based on Narrowband Scanning Light Source
  • Optical Fiber Bragg Grating Sensing System and Operation Method Based on Narrowband Scanning Light Source

Examples

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Embodiment 1

[0028] Embodiment 1 of the fiber grating sensing system based on narrowband scanning light source figure 1As shown, it includes tunable laser 1, 1X2 coupler 2, 1×4 coupler 4, circulator 5, photodetector 8 and 16 sensor channels 7. The tunable laser 1 in this example is a tunable fiber grating-based For the laser, the volume grating-based tunable laser is the same as in this case. The wavelength variation range of the narrow-band light wave whose wavelength is periodically changed by the tunable laser 1 covers the wavelength variation range of each fiber grating sensor in the system. The 1×2 coupler 2 splitting ratio of the example is 90 / 10, 90% of the laser beam is connected to the 1×4 coupler 4, and 10% of the laser beam is connected to the etalon 3. The 2 split from the 1×2 coupler 2 One of the laser channels is connected to a 1×4 coupler 4 to be divided into four sensor channels 7, and the other channel is connected to an etalon 3 as a calibration channel, and the etalon 3...

Embodiment 2

[0032] Embodiment 2 of the fiber grating sensing system based on narrowband scanning light source figure 2 As shown, its basic structure is similar to that of Embodiment 1, and its 4 circulators are replaced by 4 identical 2×1 couplers 13, and the etalon 3 of this example is F-P (Fabry-Perot Fabry-Perot) standard Tool.

[0033] The tunable laser 1 is a ring cavity tunable laser based on an F-P filter, including a pump laser 1-1, a wavelength division multiplexer 1-2, an erbium-doped fiber 1-3, and a laser 1×2 coupler 1- 4. Tunable F-P filter 1-5 and fiber isolator 1-6; the laser output from the pump laser 1-1 is connected to the wavelength division multiplexer 1-2, and the output of the wavelength division multiplexer 1-2 is sequentially connected to the doped Erbium fiber 1-3, laser 1×2 coupler 1-4, tunable F-P filter 1-5 and fiber isolator 1-6, the output end of fiber isolator 1-6 is also connected to wavelength division multiplexer 1 The input end of -2 constitutes the r...

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Abstract

The present invention is a fiber grating sensing system and operating method based on a narrow-band scanning light source. The narrow-band light-wave laser beam output by the system's adjustable laser with a periodically changing wavelength is divided into N paths and incident into N sensor channels, and the wavelength of each sensor channel is FBGs with non-overlapping change ranges are arranged according to the characteristic wavelength from short to long, and their positions from near to far. The other way enters the etalon of the calibration channel, the reflected light of each sensor channel and the transmitted light of the etalon are respectively connected to the FPGA through each photodetector and signal conditioning circuit, the output terminal of the FPGA is connected to the industrial computer, and the control signal is connected to the adjustable laser. Its operation method is that the narrow-band laser periodically scanned by the adjustable laser enters each sensor channel, and is reflected when it is the same as the characteristic wavelength of a certain FBG. FBG wavelength variation. The invention can scan continuously, the real-time wavelength calibration accuracy reaches 1με, FPGA parallel acquisition and processing, and the demodulation speed is high.

Description

technical field [0001] The invention relates to fiber grating sensing technology, in particular to a fiber grating sensing system and an operating method based on a narrow-band scanning light source. Background technique [0002] At present, most fiber grating sensing systems are composed of broadband light sources, optical beam splitters, fiber grating sensors, tunable filter devices, photodetectors and corresponding circuit systems. Under the influence of environmental strain or temperature change, the reflection wavelength of the fiber grating sensor changes. After passing through the tunable filter device, it is received by the photodetector and demodulated by the circuit system to obtain the current reflection wavelength. Compared with the initial wavelength, according to The change of the current reflection wavelength can obtain the strain or temperature change of the sensor location of the fiber Bragg grating. [0003] Since only a small part of the broadband light s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B11/16G01K11/32G01K11/3206
Inventor 杨军王航魏帅阳华岳耀笠程犁清
Owner NO 34 RES INST OF CHINA ELECTRONICS TECH GRP
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