Brillouin optical time domain analyzing and sensing system based on ultra-long annular laser pumping

Abstract

The invention discloses a Brillouin optical time domain analyzing and sensing system based on ultra-long annular laser pumping. The Brillouin optical time domain analyzing and sensing system based on the ultra-long annular laser pumping comprises first-order raman pump light (16) with the wavelength of 13 xxnm, a wavelength division multiplexer WDM pair (17) and a sensor fiber (18), wherein the wavelength division multiplexer and the sensor fiber form an ultra-long distance annular laser resonant cavity, the first-order raman pump light is fed back by the annular laser resonant cavity to generate lasing light with the wavelength of 14 XXnm. The lasing light with the wavelength of 14 XXnm performs second-order raman amplification on probe light with wavelength of 15 XXnm and Brillouin pumping. In comparison with a Brillouin sensing system based on linear cavity amplification, sensing signals are distributed more smoothly along the optical fiber, and the consistency of sensing quality in the whole process is remarkably improved; noise transfer of pumping-signal relative strength can be effectively suppressed, and temperature, spatial resolution of strain detection and measurement accuracy can be substantially improved; due to the fact that an extra second-order pump light source does not need to be added, substantial stretching of the sensing distance is obtained with low cost, and the Brillouin optical time domain analyzing and sensing system based on the ultra-long annular laser pumping has certain practicability.

Description

technical field [0001] The invention relates to the field of optical fiber technology, in particular to a Brillouin optical time-domain analysis sensing system based on ultra-long ring laser pumping. Background technique [0002] The Brillouin Optical Time Domain Analyzer (BOTDA) can realize long-distance sensing of temperature and strain. It has developed into a practical optical fiber sensing technology and is currently widely used in temperature and strain sensing of oil pipelines, high-voltage cables, and bridge buildings. monitor. [0003] The physical mechanism of BOTDA is based on the stimulated Brillouin scattering (SBS) of optical fiber. The Brillouin probe light and pump light are input from both ends of the sensing fiber, and the beat frequency produces a grating moving at the speed of sound. Under the Doppler effect, the grating produces a frequency shift of about 10-12GHz for the Brillouin pump. The scattered light and finally the probe light is amplified due ...

AI Technical Summary

Problems solved by technology

[0007] The problem to be solved by the present invention is: how to provide a Brillouin optical time-domain analysis sensing system based on ultra-long ring laser pumping, which aims to effectively improve the whole process consistency of sensing performance, and at the same time overcome the pump-signal Relative intensity noise RIN transfer problem and can be widely used in long-distance temperature / strain sensing, greatly improving the measurement accuracy and spatial resolution of the entire sensing fiber

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