Real-time correction method of tunable fiber grating wavelength demodulator

Abstract

The present invention discloses a real-time correction method of a tunable fiber grating wavelength demodulator. The method comprises the following steps that: a light source is modulated, so that sweep-frequency light with wavelength-time linearity can be obtained; the sweep-frequency light passes through a crystal type comb filter and a to-be-measured grating, so that a comb spectrum and a to-be-measured spectrum are obtained; the wavelength values of the comb spectrum are measured precisely through a spectrograph; a corresponding number of comb spectrum optical power values are obtained according to the sampling rate of the spectrograph, and the wavelength of the comb spectrum and the comb spectrum optical power values are saved so to be adopted as corrected reference; the comb spectrum and the to-be-measured spectrum are converted into electrical signals through a photoelectric conversion module, the electrical signals are collected, so that real-time comb spectrum power and to-be-measured grating spectrum power are obtained; and the real-time wavelength values of the comb spectrum are calculated; and a correction array is calculated, and the correction array is adopted to correct the real-time wavelength values of the to-be-measured grating, and the real wavelength values of the to-be-measured grating can be obtained.

Description

technical field [0001] The invention relates to the field of fiber grating sensing, in particular to a real-time correction method and system for a tuned fiber grating wavelength demodulator. Background technique [0002] Fiber Bragg grating wavelength demodulation technology is one of the key technologies in the sensing system. It can encode the sensed information in wavelength without compensating for the loss of the connector and the fluctuation of optical power. It has been widely used. [0003] At present, there are several typical demodulation methods: spectrometer detection method, matching grating detection method, tunable filter detection method, tunable light source detection method, CCD spectroscopic method, unbalanced M-Z interferometer detection method, etc. Among them, spectrometers, interferometers and other methods have many precision optical devices in the instruments, which cannot withstand tiny vibrations, so they are mostly used in laboratories. The tuna...

AI Technical Summary

Problems solved by technology

At present, tunable wavelength demodulators are mostly used for qualitative analysis of substances, such as whether fire occurs, whether invasion occurs, etc.; while in the field of quantitative analysis that requires higher precision, such as temperature modeling in chemical reactions, different species Intrusion modeling and so on are still basically unavailable. The bottleneck restricting the development of tunable wavelength demodulators lies in their low measurement accuracy and poor wavelength repeatability, especially the changes in ambient temperature will cause great differences in demodulation results. The demodulation wavelength is relatively small at low temperature, and the demodulation wavelength is relatively large at high temperature, such as figure 1 shown

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