A dual light source self-calibration optical fiber distribution temperature rapid measurement system and method

Abstract

A dual light source self-calibration optical fiber distributed temperature rapid measurement system and method, belonging to the technical field of optical fiber sensing. The system includes a computer, a multi-channel synchronous sweep lock-in amplifier, a light source drive circuit, a short-wavelength semiconductor laser, a long-wavelength semiconductor laser, a fiber combiner, a fiber coupler, a Raman wavelength division multiplexer, an optical detection module and a measurement unit. warm fiber. The two channels of different frequency signals generated by the multi-channel synchronous frequency-sweeping lock-in amplifier respectively perform step frequency modulation on the two semiconductor lasers, and the dual-frequency cross-correlation detector performs synchronous measurement on the backward Raman scattered light of two different frequencies. Fast self-correcting distributed temperature demodulation using incoherent optical frequency-domain reflectometry. The invention can complete the measurement of the optical fiber backscattering curve with dual light sources in one measurement period, which is half the measurement time of the traditional method, and provides a very competitive method for the low-cost, high-precision and high-reliability optical fiber distribution temperature measurement. powerful technical solutions.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and relates to a dual-light source self-correcting optical fiber distributed temperature rapid measurement system and method. Background technique [0002] The optical fiber distributed temperature sensor (DTS) calculates the temperature of the optical fiber according to the intensity of the backward anti-Stokes Raman scattered light of the laser in the optical fiber. It is an intensity modulation sensing method. The Stokes scattered light intensity compensates the light source intensity and optical transmission loss to a certain extent, but since the Stokes and anti-Stokes scattering channel intervals are on the order of hundreds of nanometers, if the system is calibrated for temperature, the fiber transmission loss is within two If there is a disproportionate change in this scattering band, the temperature measurement will be in error. Under high temperature or high pressure envi...

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Problems solved by technology

[0004] The purpose of the present invention is to propose a dual-light source self-correcting optical fiber distribution temperature rapid measurement system and method, aiming to solve the problem of twice the measurement time caused by wavelength switching in the traditional method, reduce the optical path loss, and improve the system performance index. Expand more space for the application of fiber optic sensors in fields such as oil and gas well exploitation

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