Fiber grating demodulating system with real-time reference

Abstract

The invention discloses a fiber grating demodulating system with real-time reference, which comprises a light path part, a circuit part, an upper computer and a software program. A reference light path with a precise Fabry-Perot cavity is in parallel connected through a coupler and an isolator on the basis of an original demodulating system based on a Fabry-Perot tunable filter demodulation method, and the measurement result of a measured light path can be corrected in real time through the measurement value of the reference light path, so that demodulation accuracy can be enhanced; two photoelectric signals are acquired and encoded by an underlying hardware circuit and then transmitted to the upper computer, a peak value position is extracted by adopting a Gaussian fitting algorithm on the upper computer, and real-time reference is carried out on the measured light path by utilizing the standard value of the reference light path. The method disclosed by the invention effectively solves the problem of demodulating accuracy degradation caused by the principle errors, namely a time-drift error, a temperature drift error, a hysteresis error, and the like, of a Fabry-Perot tunable filter, thereby providing a new exploring direction for the construction of the fiber grating demodulating system disclosed by the invention.

Description

technical field [0001] The invention belongs to the field of fiber grating sensing, and relates to a wavelength demodulation system of fiber grating sensing, in particular to a fiber grating demodulation system with real-time reference. Background technique [0002] With the maturity of fiber grating preparation technology, fiber gratings are gradually used in the field of sensing. Compared with traditional electrical sensors, fiber gratings have many characteristics such as wavelength coding, absolute reference, strong anti-electromagnetic interference ability, stable chemical properties, small size, light weight, convenient fabrication, easy large-scale low-cost production, and easy reuse. It has significant advantages in quasi-distributed measurement of important physical quantities of large structural parts (such as: strain, temperature, pressure, acceleration, etc.) and structural health monitoring of large civil engineering. Therefore, in recent years, fiber grating s...

AI Technical Summary

Problems solved by technology

These phenomena will cause time drift and temperature drift in the whole system, thereby deteriorating the demodulation accuracy

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