Distributed optical fiber sensing device and method based on Brillouin Er-doped fiber laser

Abstract

The invention relates to distributed optical fiber sensing technology and provides a distributed optical fiber sensing device and a method based on a Brillouin Er-doped fiber laser. The distributed optical fiber sensing device and the method based on the Brillouin Er-doped fiber laser comprise a narrow linewidth pump laser, an optical fiber coupler, an optical pulse generator, an optical pulse amplifier, an optical fiber amplifier, an optical fiber circulator, sensing optical fibers, a Brillouin Er-doped fiber laser, an optical fiber isolator, an photoelectric detector and a signal collecting and processing device. Brillouin gain optical fibers of the Brillouin Er-doped fiber laser are wound on piezoelectric ceramic, and Brillouin frequency shift is changed through adjusting temperature of the Brillouin gain optical fibers and / or convergent-divergent of the piezoelectric ceramic. According to the distributed optical fiber sensing device and the method based on the Brillouin Er-doped fiber laser, pump light needed by a Brillouin optical time domain analysis meter (BOTDA) and detecting light which is provided with the Brillouin frequency shift and is tunable are obtained with the same light source, and no additional laser or high-speed modulator and microwave modulating source of the high-speed modulator is needed. The system cost is lowered, the system structure is simplified, and the system structure is enabled to be compact and convenient to pack.

Description

technical field [0001] The invention relates to distributed optical fiber sensing technology, in particular to a distributed optical fiber sensing technology based on Brillouin scattering. Background technique [0002] Distributed optical fiber sensors use the optical fiber itself as both the sensing body and the transmission medium, and can accurately measure information such as stress, temperature, vibration, and damage at any point along the optical fiber, and realize long-distance, continuous distributed monitoring. Based on the outstanding characteristics of distributed optical fiber sensors, it is widely used in the security of national defense and the safety of people's lives and property, oil and gas transportation pipelines, power networks, urban infrastructure, structural health monitoring of large buildings, early warning of fires and landslides, and aircraft, It has significant technical advantages and broad application prospects in damage monitoring of ships and...

AI Technical Summary

Problems solved by technology

One solution is to use two lasers as pump light and probe light respectively. The frequency difference of the output light of the two lasers can be adjusted around the Brillouin frequency shift of the fiber. The disadvantage of this solution is that the frequency of the laser itself is stable. The performance requirements are relatively high, and complex frequency locking and frequency discrimination techniques are required to control and measure the frequency difference between the two lasers; the other is the method of using electro-optic modulator microwave frequency shifting, which is widely used at present, and the same light source is used to obtain the required Pump light and probe light, but this solution requires an expensive high-speed electro-optic modulator and a tunable high-frequency microwave signal source, and the frequency shift of the electro-optic modulator has the problems of unstable output optical power and multiple sidebands

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