Large-capacity fiber grating sensing and monitoring system

Abstract

The invention discloses a large-capacity fiber grating sensing and monitoring system, which belongs to field of fiber sensing, comprising a broadband light source, a tunable filter, a signal processing system, a photodetector, 1 x 2 couplers, 1 x 8 optical switches, 8 optical splitters, 32 fiber delay lines, and 32 fiber Bragg grating sensors which are connected in serial. The sensing network is arranged through connecting fiber grading sensors of different centre wavelengths in serial and connecting a plurality of sensors in parallel, through the time delay of the fiber delay line, the reflected signals of different paths are separated in time sequence, therefore, the signal processing system can distinguish the source of the signal according to the differences of the receiving time combining with the number information stored in the memory, realizes the combination of the time division multiplex and the wavelength division multiplex, the number of measuring points is four times that of the only-used the wavelength division multiplex, is dependent on the length difference of the time-delay fiber, the impulse width and the duty ratio, therefore, the number of measuring points is more, the measuring range is large, and multi-point distributed large-capacity monitoring can be conducted.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a multi-point distributed large-capacity optical fiber grating sensing and monitoring system. Background technique [0002] Sensors have a wide range of applications and have been a research hotspot for many years. Because fiber grating sensors have a series of advantages such as no electromagnetic interference, safety, convenience for networking and long-distance telemetry, corrosion resistance and suitable for harsh environments, it has gradually become one of the mainstream development directions of the new generation of sensors. [0003] As an optical device, a fiber grating establishes a periodic distribution of spatial refractive index in an optical fiber, and is a device in which the propagation characteristics of light can be changed. When a broadband light source is incident on a fiber Bragg grating, the central wavelength λ of its reflected li...

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Problems solved by technology

Therefore, limited by the above two factors, the number of fiber grating sensors deployed in the above demodulation method is very limited

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