Distributed Fiber Optic Sensing System

Abstract

A distributed optical fiber sensing system comprises a Raman pulse pump light source for generating Raman pulse pump light, a first pump light branching device, a first Raman signal attenuator, a first wavelength division multiplexer, a second wavelength division multiplexer, a first sensing optical fiber, a second sensing optical fiber and a Raman signal processing and control device. The distributed optical fiber sensing system branches the Raman pulse pump light generated by the Raman pulse pump light source through the first pump light branching device so as to reduce power and processes one path of the Raman pulse pump light through the first Raman signal attenuator so as to prevent the stimulated Raman scattering effect, and therefore long-distance transmission is achieved.

Description

technical field [0001] The invention relates to an optical sensing system, in particular to a distributed optical fiber sensing system. Background technique [0002] In recent years, the distributed optical fiber sensing system based on the Raman scattering effect has been developed rapidly. However, because the Raman scattering signal light is very weak, the signal intensity is generally increased by increasing the pulse pump light power. However, with the increase of the pulse pump light power, the nonlinear effect of the fiber appears, and even the stimulated Raman scattering effect appears. Once stimulated Raman scattering occurs, the Raman signal will increase abnormally, making it impossible to demodulate normal sensing information. In the commonly used distributed optical fiber sensing system, the pulsed pumping light is generally injected into the sensing fiber nearby, and the pulsed pumping light and Raman signal light are transmitted in the same fiber, so the high...

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Problems solved by technology

However, with the increase of the pulse pump light power, the nonlinear effect of the fiber appears, and even the stimulated Raman scattering effect appears.

Once stimulated Raman scattering occurs, the Raman signal will increase abnormally, making it impossible to demodulate normal sensing information

In the commonly used distributed optical fiber sensing system, the pulsed pumping light is generally injected into the sensing fiber nearby, and the pulsed pumping light and Raman signal light are transmitted in the same fiber, so the higher the power of the pulsed pumping light, the higher the power of the sensing fiber. The longer it is, the more prone to stimulated Raman scattering effect, and stimulated Raman scattering will make it impossible to demodulate normal sensing information

Therefore, the commonly used distributed optical fiber sensing system cannot achieve long-distance transmission

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