Distributed optical fiber Raman sensing device and method based on chaotic laser

Abstract

The invention belongs to the field of distributed optical fiber sensing, and discloses a chaotic laser-based distributed optical fiber Raman sensing device and method. The device includes a semiconductor laser, and the laser light emitted by the semiconductor laser is divided into Two beams, one of which passes through the first erbium-doped fiber amplifier, nonlinear fiber, polarization controller, and circulator, and then returns to the semiconductor laser to output broadband chaotic laser; the other beam is pulse-modulated by an acousto-optic modulator to generate chaotic pulse laser It is divided into two paths through the second coupler, one path is detected by the third detector, and the other path enters the sensing fiber after passing through the wavelength division multiplexer, and returns waves after Raman scattering and Rayleigh scattering occur at each point in the sensing fiber After the demultiplexer is output, it is detected by the first photodetector and the second photodetector respectively, and the detection signal is demodulated to obtain the temperature and strain information along the sensing optical fiber. The invention can realize submillimeter-level resolution distributed optical fiber Raman sensing.

Description

technical field [0001] The invention belongs to the field of distributed optical fiber sensing, in particular to a chaotic laser-based distributed optical fiber Raman sensing device and method with submillimeter resolution. Background technique [0002] The distributed optical fiber Raman sensing system collects the Raman anti-Stokes scattered light spontaneously scattered by the sensing fiber and carries temperature information, and uses optical time domain reflectometry to continuously measure the temperature along the sensing fiber. With its small size, corrosion resistance, anti-electromagnetic interference and other advantages, the distributed optical fiber Raman sensing system is widely used in safety monitoring fields such as traffic bridges, coal mines, tunnels, and large buildings. [0003] In a distributed optical fiber Raman sensing system, the spatial resolution refers to the minimum length that can resolve the temperature change of the optical fiber. Improving ...

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Problems solved by technology

[0005] In order to solve the technical problems of low spatial resolution of the existing distributed optical fiber Raman temperature sensing system and the inability of the system to realize continuous measurement of temperature and strain at the same time, the present invention proposes a chaotic laser-based submillimeter-level resolution distribution fiber optic Raman sensing device

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