Double-core FBG (fiber bragg grating) array sensing network and distributed sensing information obtaining method

Abstract

The invention discloses a double-core FBG (fiber bragg grating) array sensing network. The output end of a scanning laser is connected with a semiconductor amplifier, and the output end of the semiconductor amplifier is connected with an optical circulator. An optical connector is connected with the optical circulator, and the optical circulator is connected a first FBG array and a second FBG array in a double-core FBG array. The optical circulator is connected with the input end of a photoelectric detector, and the output end of the photoelectric detector is connected with a grid wavelength detection electric signal input end of a demodulator. A semiconductor light amplification drive signal output end of a pulse function generator is connected with a drive signal input end of the photoelectric detector. A demodulation control signal output end of the pulse function generator is connected with the demodulation control signal input end of the demodulator. A pulse function generator drive signal output end of the demodulator is connected with a drive signal input end of the pulse function generator. The network is high in stability, is low in loss, and has no temperature interference.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing and detection, in particular to a dual-core optical fiber grating array sensing network and a distributed sensing information acquisition method. Background technique [0002] Fiber Bragg grating sensors have the advantages of high sensitivity, anti-electromagnetic interference, corrosion resistance, wide dynamic measurement range, small size, and easy reuse, so they have been widely studied and used. Fiber Bragg grating is a special kind of optical fiber in which the refractive index of the fiber core is permanently and periodically modulated. The central wavelength of its emission spectrum is a physical quantity related to the refractive index of the fiber and the period of the perturbation of the refractive index. When the external physical quantity changes, the refractive index and period of the grating are changed, thereby changing the central wavelength of the reflection spect...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the packaging method is prone to chirp problems in the reflection spectrum

[0008] At present, the sensing network of fiber grating array is a hot research direction, and it also has shortcomings and shortcomings, such as the cross influence of fiber grating on temperature and stress, low multiplexing ability, etc.

However, the traditional wavelength division multiplexing (WDM) technology is limited by the spectral width of the light source, and the multiplexing capacity can only reach dozens of

Time division multiplexing (TDM) technology can greatly increase the multiplexing capacity of the system in the time domain, but the transmission attenuation and light source intensity are limited, and the number of multiplexed gratings is only dozens

In addition, frequency division multiplexing (FDM) technology and code division multiple access multiplexing (CDMA) technology are also limited by bandwidth and transmission loss to a certain extent.

How to improve the multiplexing capability of the sensor network and the separate sensing of fiber grating temperature and strain are the key points and difficulties, and the above methods are difficult to meet the requirements

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