Physical quantity measurement method based on intensity modulation type fiber sensor

Abstract

The invention provides a physical quantity measurement method based on an intensity modulation type fiber sensor. According to the invention, laser generated by a laser passes an intensity modulator and then enters a coupler in the form of laser pulse to be divided into two paths, wherein one path is connected to a sensing unit and the other path is connected to a reference unit; two paths of light pulses of the sensing unit and the reference unit pass respectively fibers and then are reflected back to the coupler through fiber reflection mirrors connected to the back ends of the fibers respectively; outputting signals with sensing information are received on the other end of the coupler; and the output light pulse signals are converted by a photoelectric detector and then enter a data acquisition module. Thus, under the condition that a new disturbance source is not introduced, adverse effects caused by fluctuation of light pulse sources and disturbance of devices in the light paths can be eliminated; interference of intensity noise of the system is effectively eliminated; and the stability of the fiber intensity modulation type sensor and the minimum resolution of the system are remarkably improved.

Description

technical field [0001] The invention relates to the field of sensing technology, in particular to a physical quantity measurement method based on an intensity modulation optical fiber sensor. Background technique [0002] Optical fiber sensors have the characteristics of small size, strong anti-interference ability, high sensitivity, good reliability, long-distance sensing and easy multiplexing, etc., and have received great attention in the field of sensing since they came out. [0003] According to the change of the characteristic parameters of the optical pulse wave caused by the measured disturbance, the optical fiber sensing technology can be divided into five types: intensity modulation type, wavelength modulation type, frequency modulation type, phase modulation type and polarization modulation type. Among them, the basic principle of the intensity modulation optical fiber sensing technology is to disturb the intensity of the transmitted light pulse in the optical fib...

AI Technical Summary

Problems solved by technology

The optical pulse source feedback control method can effectively control the fluctuation caused by the optical pulse source, but on the one hand, this method will increase the complexity of the system and cannot eliminate the influence of the spurious intensity modulation of the optical path

Using a coupler to extract part of the optical pulse as a reference optical pulse can also partially suppress the fluctuation of the optical pulse source and the parasitic intensity modulation of part of the optical path, but this method introduces a new parasitic intensity modulation, which makes the suppression effect of the optical pulse intensity fluctuation not good. Even worse, at the same time, this method requires two sets of detectors and detection circuits, and adding new equipment will introduce new sources of noise

In addition, there are dual-wavelength methods, optical fiber network methods, neural network compensation methods, etc. These methods either increase the complexity of the system while suppressing the original intensity noise, or introduce new noise sources, or because of structural reasons while limiting its scope of application

Therefore, it is difficult to effectively improve the measurement performance and application value of intensity-modulated fiber optic sensors.

Difficulty in improving detection accuracy hinders the application of intensity-modulated optical fiber sensing technology in the field of high-precision detection

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