Dual wavelength light source self-correcting distributed optical fiber Raman temperature sensor for optical fiber Raman frequency shifter

Abstract

The invention discloses a dual wavelength light source self-correcting distributed optical fiber Raman temperature sensor for an optical fiber Raman frequency shifter. The dual wavelength light source self-correcting distributed optical fiber Raman temperature sensor comprises an optical fiber pulsed laser, an optical fiber branching device, the optical fiber Raman frequency shifter which consists of a monomode optical fiber and a 1660nm light filter, two optical fiber wavelength division multiplexers, two optical fiber switches, a sensing optical fiber, a photoelectric receiving module, a digital signal processor and an industrial personal computer. In the sensor, a Raman-related dual wavelength light source is obtained by one optical fiber pulsed laser through the optical fiber Raman frequency shifter; nonlinear loss caused by bending and compression tension generated by the optical fibers and optical cables is self-corrected when temperature-measuring optical fibers and optical cables are used on site; and a temperature-measuring error caused by deviation from linearity when an anti-Stokes Raman signal channel is demodulated by a Stokes Raman reference channel in a temperature-measuring system is overcome. The dual wavelength light source self-correcting distributed optical fiber Raman temperature sensor is low in cost, long in service life, simple in structure, high in signal to noise ratio and reliability, and suitable for remote petrochemical pipeline, tunnel and large-scale civil engineering monitoring and disaster forecast monitoring in the range of 30 kilometers.

Description

technical field [0001] The invention relates to an optical fiber Raman temperature sensor, in particular to an optical fiber Raman frequency shifter dual-wavelength light source self-correcting distributed optical fiber Raman temperature sensor, belonging to the technical field of optical fiber sensing. Background technique [0002] In recent years, a distributed optical fiber Raman temperature sensor has been developed by using the effect of optical fiber Raman scattered light intensity modulated by temperature and the principle of optical time domain reflectance (OTDR), which can predict the temperature and the orientation of temperature changes on-site in real time, and monitor on-site It is an intrinsically safe linear temperature-sensing detector, which has been successfully applied in the fields of electric power industry, petrochemical enterprises, large-scale civil engineering and online disaster monitoring. [0003] Since the optical fiber loss in each band is diffe...

AI Technical Summary

Problems solved by technology

However, two light sources, the main light source and the secondary light source, are relatively complex and expensive, and cannot fully meet the safety and health monitoring of oil pipelines and transmission power cables in recent years. Urgent needs

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