Optical fiber grating temperature sensing demodulation method

Abstract

The invention relates to a sensing demodulation method based on an optical fiber grating temperature sensing demodulation system, which is implemented based on the combination of a Mach-Zehnder interferometer and a photoelectric oscillator. The sensing demodulation system mainly comprises a broadband light source, an optical fiber circulator, an optical fiber grating, an optical fiber coupler, a single-mode optical fiber ring, a dispersion optical fiber ring, an electro-optic modulator, a dispersion optical fiber, a high-speed photoelectric detector, a low noise amplifier, a microwave power divider, a frequency spectrograph and a computer. The optical fiber grating will cause the wavelength shift of emitted light thereof when the temperature changes so as to enable the optical path difference of the Mach-Zehnder interferometer to change, so that the central frequency of a microwave signal outputted by the photoelectric oscillator is changed, the wavelength shift of the reflected lightof the optical fiber grating is obtained according to the variation of the central frequency of the microwave signal, and finally optical fiber grating temperature sensing is realized. The temperaturesensing demodulation system is not only high in accuracy, but also adjustable in measurement sensitivity and stable in measurement result.

Description

technical field [0001] The invention belongs to the field of optical fiber grating sensing and demodulation, in particular to a method for optical fiber grating temperature sensing and demodulation based on a photoelectric oscillator. Background technique [0002] Fiber Bragg grating is a passive filter device. Due to its small size, full compatibility with optical fibers, and the ability to embed smart materials, etc., and its harmonic wavelength is sensitive to changes in external environmental factors such as temperature and strain physical quantities, it is used in sensing field has been widely used. Fiber Bragg grating sensor obtains sensing information by modulating the center wavelength of fiber Bragg with external parameters. It has the advantages of anti-electromagnetic interference, high sensitivity, low cost, and good compatibility with ordinary optical fibers, so it has attracted more and more attention. [0003] At present, the fiber grating sensing demodulatio...

AI Technical Summary

Problems solved by technology

The temperature sensitivity of ordinary fiber gratings is about 0.010nm / °C. For a fiber grating with a working wavelength of 1550nm, the wavelength change of the measurement temperature in the range of 100°C is only 1nm, which cannot meet the needs of actual measurement.

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