Fiber bragg grating track sensing system based on optical code division multiple access technique

Abstract

The invention discloses a fiber bragg grating track sensing system based on an optical code division multiple access technique. An encoding optical pulse emitted by a broadband light source under the control of a control and analysis unit enters a plurality of sensing fiber bragg grating arrays arranged along a track through an optical isolation unit, the reflected light of the fiber bragg grating arrays enters a modulating circuit in an electrical signal mode for I-V conversion and voltage amplification after entering a photoelectric receiving unit through an optical filter, and a digital-to-analog converter samples the amplified voltage signals to convert the voltage signals to digital signals and then transmitting the digital signals to the control and analysis unit for analysis so that the modulation result of the measured physical quantity is obtained; and the used encoding sequence and the length and the bit time slots thereof are stored by the control and analysis unit. Compared with the sensing system using the traditional fiber bragg grating network multiplexing technique, the invention has the advantages of simple structure, flexible networking, greatly increased multiplexing quantity, high modulating speed and the like and is especially suitable for the quasi-distribution type measurement of a plurality of physical quantities in the large range of track traffic line.

Description

technical field [0001] The invention relates to the use of optical code division multiple access technology (OCDMA) optical fiber grating sensing system in rail traffic (railway traffic, urban subway traffic, light rail traffic, mine rail traffic) to realize the monitoring of track temperature, pressure or strain information . Background technique [0002] Fiber Bragg Grating (or called Fiber Bragg Grating, Fiber Bragg Grating-FBG) is a hotspot in the field of sensing research and application. Compared with conventional sensing technologies, fiber grating sensors have many excellent properties such as anti-electromagnetic interference and atomic radiation, light weight, small size, insulation, high temperature resistance, corrosion resistance, etc., and are more and more favored by special occasions or harsh environment applications . Fiber grating sensors have been widely used in civil engineering (bridges, mines, tunnels, dams and buildings, etc.), aerospace, marine, med...

AI Technical Summary

Problems solved by technology

The traditional grating multiplexing network is limited by the number of multiplexing and demodulation speed, and cannot meet the requirements of the rail transit field for a quasi-distributed sensor network system with a wide range and high demodulation speed

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