FBG Demodulation System Based On Non-uniform Sampling

As the fiber bragg grating sensor has excellent high insulating properties, strong inductive interference protection, resistance to corrosion and chemical stability, making it possible to work properly at high temperatures, high humidity, high pressure, strong noise, corrosive and many other special environment. Fiber optic sensors are in line with fiber optic remote sensing and the telemetry to constitute the optical fiber remote sensing system and fiber optic telemetry systems, and have absolute superiority in the sensing area compared with conventional electrical sensors. The rapid development of optical communication technology and continuous progress of grating written technology provide huge opportunities for the development of fiber Bragg grating sensors.This paper describes a FBG demodulation system based on non-uniform sampling, the sine wave which cycles random variations is used to implement non-uniform sampling, further improve the measurement bandwidth of FBG sensing demodulation device. Based on four times of the sampling rate created by SI-FBGs. Solved the problem of signal distortion caused by the non-uniform sampling for based on tunable F-P filter overlapping multi-grating demodulation device, improve the application range and flexibility of the sensing fiber grating, both measuring accuracy and demodulation bandwidth were met simultaneously.On basis of depth study of the principle of FBG demodulation and existing fiber grating demodulation techniques, the paper finalized the determination is based tunable F-P filter FBG demodulation scheme, and detailed analysis the factors affecting system performance. Master the working principle and performance parameters of grating demodulation system components; Analysis the demodulation and sensing principle of FBG sensing system; Design hardware, build up fiber grating demodulation system test platform based on non-uniform sampling; Focuses on the non-uniform sampling method; Introduced of non-uniform sampling algorithm principles; Verified the non-uniform sampling anti-aliasing algorithm characteristics from the perspective of simulation experiments and practical orientation respectively.The results confirmed that the non-uniform sampling algorithm can analyze the measured signal below the Nyquist sampling frequency and able to completely restore the original signal in the frequency domain without causing distortion and aliasing. Combination of non-uniform sampling and overlapping dual grating could improve system performance significantly.