Fiber Raman frequency shifter double-wavelength pulse coding light source self-correcting distribution type fiber Raman temperature sensor

Abstract

The invention discloses a fiber Raman frequency shifter double-wavelength pulse coding light source self-correcting distribution type fiber Raman temperature sensor which comprises a pulse coding fiber laser driving power supply, a pulse coding fiber laser, a fiber shunt, a fiber Raman frequency shifter, two fiber wavelength division multiplexers, two fiber switches, a sensing fiber, a photoelectric receiving module, a digital signal processor and an industrial personal computer, wherein the sensor obtains a Raman relevant double-wavelength light source by the fiber Raman frequency shifter with a pulse coding fiber laser, bend because of fibers and optical cables and nonlinear loss caused by pressed stretching when a temperature measuring optical fiber cable is used on site are subjected to self correction. Measurement errors caused by deviation from linearity when a Stokes Raman reference channel demodulates an anti-Stokes Raman signal channel in the temperature measuring system are overcome. The fiber Raman frequency shifter double-wavelength pulse coding light source self-correcting distribution type fiber Raman temperature sensor has the advantages of low cost, long service life, simple structure, good signal to noise ratio and good reliability, and is suitable for monitoring petrochemical pipelines, tunnels and large civil engineering within the very long range of 80 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 pulse coded 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 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 in real time online, and monitor the 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 b...

AI Technical Summary

Problems solved by technology

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

Images