Sensing demodulating system for optical chirped-grating

Abstract

The invention relates to a sensing demodulating system for an optical chirped-grating. The system is composed of two parts: a sensing part and a demodulation part; wherein the sensing principle of the system is as follows: when external physical parameters change, envelope area of a reflection spectrum used for sensing optical chirped-grating changes accordingly; the demodulation part is strength type demodulating equipment which is mainly composed of a broadband light source, a demodulation light path, an O/E and signal processing circuit. Optical signals are emitted from the broadband light source, the sensed grating is partially reflected back to the demodulating equipment, the reflected optical signals are divided into two paths through a branching unit with one path of the optical signals directly transmitted to a photoelectric detector and the other path of the optical signals reflected through a reference grating before being received by another photoelectric detector. The last two paths of electrical signals are processed by the signal processing circuit to obtain output result of the system; the result output is free from influence of the light source and light power fluctuation of a transmission light path, thus achieving the purpose of improving system accuracy. In addition, the invention has the characteristics of simple structure, low cost and applicability to both dynamic and static measurement.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing, and is especially used for intensity demodulation of optical fiber chirped grating sensors; the sensing demodulation system is suitable for both dynamic and static measurement of physical parameters, and can realize high-speed demodulation. Background technique [0002] Fiber Bragg grating sensors have the characteristics of high reliability, anti-electromagnetic interference, and anti-corrosion, and are widely used in engineering fields. Fiber Bragg grating sensing technology involves multiple disciplines such as materials, physics, chemistry, electromechanical, information, etc. One of the most critical technologies that restricts its large-scale engineering application is fiber Bragg grating sensing and demodulation technology. At present, the dominant demodulation technology in engineering applications is FBG wavelength demodulation technology based on F-P filter. This technology has man...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned technology, provide a kind of sensitive element that utilizes the optical fiber chirped grating as the sensing system, adopt the intensity demodulation mode with simple structure, low cost to realize the detection of physical parameter, solve the problem of intensity demodulation The method is affected by the fluctuation of the optical power of the light source and the loss of the light intensity of the transmission optical path, and realizes the high-precision measurement of the intensity-type demodulation

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