Synthetic fiber grating digital demodulation and regional temperature monitoring method and system

Abstract

The invention discloses an identical optical fiber grating digital demodulation and regional temperature monitoring method and system thereof, wherein the method includes the following steps: sampling the optical fiber grating reflection spectrum power signal to obtain sampling data at equal time intervals; Sampling at equal intervals, and performing a forward difference on the sampled data, and judging the rough position of the bottom and top of the grating reflection peak through the sign change of the difference result; if the difference between the top power and the bottom power is greater than or equal to the preset peak height threshold, then the The peak is the reflection peak of the grating; the peak power of the reflection peak is calculated according to the sampling data near the top of the reflection peak of the grating; the dynamic threshold is obtained by attenuating the power of the peak top, and the time corresponding to the intersection point of the dynamic threshold and the sampling data of the reflection peak in the long wavelength direction As the front time, the front wavelength is calculated according to the front time; the real-time temperature of the area is calculated according to the front wavelength. The invention can effectively distinguish the variable of the wavelength and truly reflect the actual temperature change in the region.

Description

technical field [0001] The invention relates to digital demodulation of optical fiber gratings, in particular to an identical optical fiber grating digital demodulation and regional temperature monitoring method and system thereof. Background technique [0002] Fiber Bragg grating sensors are widely used in the field of temperature monitoring. At present, fiber gratings of different wavelengths are connected in series to form a sensing array, but this method is limited by the wavelength range of the demodulation instrument. For example, if the wavelength range of the demodulation instrument is 40nm, it can only carry up to 20 fiber grating sensors with different wavelengths. In practical applications, fire monitoring systems such as oil tanks and tunnels usually require temperature monitoring in a large area. The use of point-by-point fiber grating sensors faces the dual limitation of sensing range and sensor density. [0003] In order to solve the above problems, it is exp...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a method that can effectively distinguish the wavelength variable and perform temperature conversion due to the overlap of center wavelengths in the prior art when using identical fiber gratings. Identical fiber grating digital demodulation and regional temperature monitoring method and system for temperature conversion

Images