Multi-channel fiber Bragg grating (FBG) demodulator

Abstract

The invention discloses a multi-channel fiber Bragg grating (FBG) demodulator, which adopts a scanning fiber laser as a light source. The scanning fiber laser is on the basis of a micro-mechanical structural filter with temperature control, and belongs to a narrow-linewidth and high-coherent light source which is calibrated accurately. The calibration is implemented by a thermostable FP etalon with a wavelength label. A gain matching fiber amplifier amplifies the power of the output of a laser and achieves the power flatness of scanning laser spectroscopy. A fiber Bragg grating reflected signal enters a data acquiring and processing system after passing through a photoelectric detector and an AD converter processing module. A data acquiring and processing and peak detection system is implemented by adopting an FPGA-based all-digital scheme, and simultaneously utilizes a synchronous signal of a direct numerical frequency synthesis module to obtain a control voltage of the micro-mechanical structural filter. By combining with other equipment, the scanning fiber laser, the etalon and the FPGA realize the multichannel, high-precision, high-stability, high-repeatability, and serial-parallel structure detection of a grating sensor network signal.

Description

technical field [0001] The invention relates to a multi-channel fiber grating demodulator, in particular to a multi-channel demodulator which utilizes scanning fiber laser technology to realize fiber grating sensor network detection. Background technique [0002] The quasi-distributed optical fiber stress and temperature sensing system based on fiber grating has very important application value, and has a very wide range of applications in electric energy, petrochemical industry, industrial and civil construction and other fields that require real-time temperature and stress monitoring. Using this technology can realize long-distance measurement and monitoring. It has the characteristics of wide measurement range, high precision and high resolution, and has more advantages in strong electromagnetic interference or harsh environments with inflammable and explosive substances. [0003] At present, the industrialization and large-scale promotion and application of optical fiber...

AI Technical Summary

Problems solved by technology

In this way, the light intensity obtained in the photodetector will also be very weak, which is not conducive to photoelectric detection and increases the difficulty of demodulation

[0007] (2) Channel limitation: Due to the small output power of the light source and the large attenuation of the signal, if the number of channels is increased, it will be more unfavorable for photoelectric detection after splitting, so the number of measurable fiber grating arrays is limited

Images