Demodulation method and device for optical distance variation of optical fiber interferometer sensor

Abstract

The present invention provides a demodulation method for the optical distance variation of an optical fibre interferometer sensor, including steps of (1) detecting the spectrum of the optical fiber interferometer sensor; (2) transmitting the detected spectrum to a computer for a Fourier transformation or Z spectrum conversion to obtain an amplitude spectrum and a phase spectrum of an optical fiber interferometer sensor reflected signal; (3) obtaining an approx center frequency of the optical fiber interferometer sensor from the amplitude spectrum and then fixing the frequency point to monitor the change of the point phase; obtaining the optical distance change of the optical fiber interferometer sensor by the phase spectrum. By monitoring the phase change around the center frequency point in the phase spectrum after the optical spectrum and the frequency spectrum conversion of the optical fiber interferometer sensor, it is capable of obtaining the optical distance change of the interferometer sensor, comparing with the traditional detection of the change of the intensity frequency spectrum center frequency, the sensor center frequency point of the phase spectrum is more sensitive to the optical distance difference, thus the invention has a high sensitivity or resolution.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a demodulation method and a device for optical path change of an optical fiber interferometer sensor. Background technique [0002] Optical fiber sensors have a series of advantages such as safety, immunity to electromagnetic interference, easy networking and long-distance telemetry, and suitable for harsh environments, and have gradually become one of the mainstream development directions of the new generation of sensors. [0003] Optical fiber interferometer sensing demodulation schemes can be divided into two categories: intensity demodulation and phase demodulation. The intensity demodulation method cannot be used for high-precision measurement due to its susceptibility to external interference. Phase demodulation can obtain high-resolution cavity length variation demodulation. At present, phase demodulation methods include fringe counting method, ...

AI Technical Summary

Problems solved by technology

[0004] The technical solution to be solved by the present invention is to provide a demodulation method for the optical path change of the optical fiber interferometer sensor, which can greatly reduce the requirements for the spectral sampling resolution of the interferometer sensor, and avoid the high cost of traditional spectral demodulation methods. disadvantages, while having high demodulation resolution

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