Distributed optical fiber Raman sensing device and method based on noise matched filtering

Abstract

The invention belongs to the field of distributed optical fiber sensing, and discloses a distributed optical fiber sensing device and method based on noise matched filtering, and the device comprisesan ASE noise laser which emits a noise laser signal, the noise laser signal is converted into a pulse signal through an isolator and an acoustic optical modulator, and then the pulse signal is dividedinto two beams through an optical fiber coupler. One light beam is used as a detection light beam and enters a sensing optical fiber after passing through a wavelength division multiplexer, and backward noise Rayleigh scattering light and noise Raman anti-Stokes scattering light generated in the sensing optical fiber are separated by the wavelength division multiplexer and then are amplified by afirst erbium-doped optical fiber amplifier and a second erbium-doped optical fiber amplifier respectively; and the beam is detected by a first detector and a second detector respectively, and the other beam is detected by a third detector as a reference beam; detection signals of the three detectors are collected through a collection card and sent to the computer. According to the invention, a farther sensing distance can be achieved, simultaneous sensing of temperature and stress is realized, and the resolution of the system is improved.

Description

technical field [0001] The invention relates to the field of distributed optical fiber sensing, in particular to a distributed optical fiber sensing device and method based on noise matching filtering that can realize high spatial resolution. Background technique [0002] The distributed optical fiber Raman sensing system can continuously measure the distributed temperature characteristic information along the sensing optical fiber. In the distributed optical fiber Raman sensing system, the ambient temperature along the sensing fiber can modulate the intensity of the Raman scattered light in the optical fiber. The temperature change along the sensing fiber is obtained. The distributed optical fiber Raman sensing system has the advantages of high voltage resistance, anti-electromagnetic interference, small size, and light weight, so it is widely used in temperature safety monitoring fields such as coal mines, oil and gas pipelines, bridges, and buildings. [0003] In the di...

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Problems solved by technology

[0005] In order to solve the technical problem that the spatial resolution of the existing distributed optical fiber Raman sensing system is limited by the OTDR principle, it is difficult to break through 1m, and the system cannot simultaneously realize the continuous distributed measurement of the two parameters of temperature and strain

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