A method and device for adapting light source parameters in a distributed optical fiber sensing system

Abstract

The invention discloses a method and device for self-adapting the light source parameters of a distributed optical fiber sensing system. , adjust the optical pulse repetition frequency; Step S2, calculate the standard deviation of the point scattering signal S(L-m)~S(L-n) at the end of the sensing fiber in t measurement periods, and filter to obtain the maximum value of the standard deviation σ max ; Step S3, set σ max and set the default value σ 0 Compare; step S4, if σ max >σ 0 , then increase the output power of the light source, and repeat steps S2-S3 until σ max ≤σ 0 . The invention can monitor the standard deviation of the signal at the tail end of the sensing fiber in real time. The repetition frequency of the pulsed laser is modified in real time by the microcontroller to optimize the system response time. The measured standard deviation is compared with the preset standard deviation. When the measured standard deviation is found to be less than the preset value, the output power of the light source is increased through the microcontroller to improve the signal-to-noise ratio and eliminate the performance degradation caused by the increase in fiber loss.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a method and a device for self-adapting light source parameters of a distributed optical fiber sensing system. Background technique [0002] Optical fiber sensing technology has gradually become one of the most representative emerging technologies in the field of sensing due to its passive sensing medium, corrosion resistance, anti-electromagnetic interference, and long service life. Among them, distributed optical fiber sensing technology uses optical time domain reflection technology to locate the backscattered signal at any point in the optical fiber. Therefore, it has the function of measuring the distribution of physical quantities along the optical fiber. The monitoring of relevant physical quantities in the range of several kilometers or even tens of kilometers can be realized through a single optical fiber. The backscattering signal in the optic...

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Problems solved by technology

If the repetition frequency of the detection light pulse is too slow, the single measurement time will increase, and the response time will increase significantly after accumulation and averaging, which is not conducive to fire detection and other applications that require high response time

At the same time, for different applications, different lengths and types of optical fibers are often used. The relevant parameters of the distributed optical fiber sensing system need to be manually debugged and modified, and the steps are cumbersome. , and it needs to be re-debugged and modified, and the later maintenance work is relatively large

In addition, the loss in the optical fiber is prone to change under the influence of the external environment for a long time

For example, after the long-term operation of the downhole optical cable, it is corroded by hydrogen ions and the loss increases. If the power of the incident detection optical pulse cannot be adjusted in time, the system performance will be greatly reduced.

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