Pulse-encoded distributed optical fiber raman temperature sensing method and device

Abstract

The invention discloses a pulse-encoded distributed optical fiber raman temperature sensing method and device. An any-order encoding matrix is provided, all of principal diagonal elements are 0 and all of the remaining elements are 1; each row of the matrix is sequentially injected into the distributed optical fiber raman temperature sensing device; the device comprises a semiconductor laser, a driving module, an FPGA (Field Programmable Gate Array) code modulator including an SOA (Semiconductor Optical Amplifier), an optical fiber amplifier, an optical fiber circulator, an optical fiber wavelength division multiplexer, a thermotank, a sensing optical fiber, a detector module, an A / D (Analog to Digital) module and an industrial computer. In combination with a pulse encoding principle and an optical fiber rayleigh scattering assisted demodulation raman scattering principle, the dynamic range of a sensing system is improved without changing a spatial resolution, the measurement length and measurement precision are enhanced; and the pulse-encoded distributed optical fiber raman temperature sensing method and device are suitable for measurement and disaster warning of water, oil and gas pipelines, a tunnel and a large-scale civil project in a large range.

Description

technical field [0001] The invention relates to a distributed optical fiber Raman temperature sensing device, in particular to a distributed optical fiber Raman temperature sensing method and device using pulse coding, belonging to the technical field of optical fiber sensing. Background technique [0002] ROTDR (Raman Optical Time Domain Reflectometer) is a distributed optical fiber temperature sensing system made of Raman backscattering. The optical pulse is injected into the optical fiber as a detection signal. When the optical pulse propagates along the optical fiber, the backscattering part of the Raman scattering everywhere will continue to return to the incident end of the optical fiber. Raman scattering includes Stokes and anti-Stokes light, where anti-Stokes light is sensitive to fiber temperature. By detecting the size and arrival time of the backscattered light at the input end through a suitable optical coupler and a high-speed response photodetector, the temper...

AI Technical Summary

Problems solved by technology

It can be seen that it is impossible to obtain a large dynamic range and a high spatial resolution at the same time, and the two cannot have both

Images