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 distributed optical fiber Raman sensing device and method based on chaotic laser. The device comprises a semiconductor laser, the emitted laser is divided into two beams through a circulator and a first coupler, one beam passes through a first erbium-doped optical fiber amplifier, a nonlinear optical fiber, apolarization controller and a circulator and then returns to the semiconductor laser to enable the semiconductor laser to output broadband chaotic laser, the other beam is subjected to pulse modulation through an acousto-optic modulator to generate chaotic pulse laser, the chaotic pulse laser is divided into two paths through a second coupler, one path is detected by a third detector, and the other path enters a sensing optical fiber through a wavelength division multiplexer, raman scattering and Rayleigh scattering happen to all points in the sensing optical fiber, then the signals are returned to the wavelength division multiplexer, output and then detected by the first photoelectric detector and the second photoelectric detector respectively, temperature and strain information along thesensing optical fiber is demodulated from detection signals, and submillimeter-level resolution distributed optical fiber Raman sensing can be achieved.

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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