Simulation and hardware implementation of demodulation for fiber optic seismic sensor with linear edge filtering method

Abstract The demodulation system is a very critical component of the seismic exploration, which determines the response speed and accuracy of data acquisition of the detection system. Here, we demonstrate a simulation and hardware implementation of demodulation system based on linear edge filtering method for fiber optic seismic sensor. The system is implemented mainly by an edge filter (long period fiber grating) with the linear slope of 1.368 dBm/nm and the sideband width of 6.05 nm, and a homemade circuit board. The results show that the system can be used to demodulate low-frequency (10 Hz–200 Hz) vibration signals, and the best signal-to-noise ratio is up to ~ 70 dB. Moreover, theoretically, the system could be used to demodulate higher frequency vibration and can be adapted to any vibration measurement, and suitable for engineering application due to the characteristics of simple structure, low cost, stable performance, fast response speed and high precision.