Ultra-large capacity time division and wavelength division fiber grating sensing system and query method thereof

Abstract

The invention relates to an ultra-large capacity time division and wavelength division fiber grating sensing system and a query method of the fiber grating sensing system. The ultra-large capacity time division wavelength division fiber grating sensing system consists of a broadband light source, a modulation module, a circulator, a fiber Bragg grating sensing array, a sampling module, a wavelength demodulation instrument and a data processing computer, wherein the modulation module and the sampling module comprise a SOA high-speed photoelectric switch respectively and are driven by different channels of the same signal generator, and a phase difference exists between two drive pulses; and the fiber Bragg grating sensing array can be composed of identical fiber gratings or multi-wavelength fiber gratings. With the adoption of a technology combining a time division multiplexing with a wavelength division multiplexing, tens of thousands of gratings can be engraved on an optical fiber. The ultra-large capacity time division and wavelength division fiber grating sensing system has characteristics of large system capacity, high response speed, good expandability, high flexibility, good stability, low cost and the like, can perform dynamic measurement and static measurement at the same time, and can satisfactorily meet requirements of internet of things on information capacity.

Description

technical field [0001] The invention belongs to the field of sensing technology, and in particular relates to a super-large-capacity time-division wavelength-division optical fiber grating sensing system and a query method thereof. Background technique [0002] Optical fiber sensors have the characteristics of fire and explosion protection, corrosion resistance, and anti-electromagnetic interference, and have a wider application range than other sensors. In recent years, with the continuous development of semiconductor optoelectronic technology, the research and application of fiber optic sensors have attracted much attention. The existing large-capacity distributed optical fiber sensing technology mainly uses optical time domain reflectometry (OTDR), including the use of Raman scattering (patent number 01124438.0 "distributed optical fiber temperature sensor system"), Brillouin scattering, Rayleigh scattering, etc. Methods. Although the optical fiber sensing system based ...

AI Technical Summary

Problems solved by technology

Conventional grating sensing systems mostly use wavelength division multiplexing. Between different gratings, there must be sufficient intervals between the Bragg center wavelengths. The Bragg wavelength interval of fiber gratings at different points is generally 2nm; since the bandwidth of the light source is usually only about 40nm , therefore, the number of probes that can be multiplexed in this system is very limited, which is far from meeting the actual requirements

Encoded fiber grating (patent number 200310111529.2 "Large-capacity coded fiber grating sensor monitoring system"), grouped fiber grating and other technologies are used to expand the capacity of the sensing system, because it is necessary to write multiple groups of gratings at the same position, or the grating wavelength There are strict requirements on the location and location, the sensor system constructed by the above method has a complex structure, limited expansion of system capacity, and is easily affected by the environment, so it is subject to many restrictions in application

In recent years, time-division multiplexing-based query technology has re-entered people's research field of vision. Most of the traditional methods use directly modulated light sources (Patent No. 201110031508.4 "Quasi-distributed sensor network based on time-division multiplexing and matching fiber grating technology") to obtain Light pulses, but most light sources have large junction capacitance and poor direct modulation characteristics (for example, SLED directly modulates pulse widths above 50ns), and use electrical delay technology to control and select ns-level light pulses (patent No. 201110326745.3 "based on Fiber Bragg grating sensing method and system of wavelength division multiplexing multi-channel output time-domain address query technology"), and simultaneously detect the optical pulse trains reflected by multiple gratings, the time-domain resolution is poor, and the crosstalk between pulses is serious

High-speed circuits need to separate reflected signals and process information in ns-level time. Existing circuit technology is difficult to implement, the system is complex, the real-time performance is poor, and the cost is expensive. There are no reports on related applications.

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