Study on phase demodulation algorithm of fiber optic pressure sensor based on nonlinear differential equation

Fiber optic Fabry–Pérot sensors have been widely developed with unique advantages, such as ease of reuse, resistance to electromagnetic interference, light weight, and their ability work in extreme environments. There are many demodulation methods that can be applied fiber sensors, including the intensity method, spectral demodulation, phase carrier but these cannot meet requirements take into account range, speed, dynamic static capabilities. In view problems, this paper uses nonlinear differential equations solve problem simultaneous measurement a large number ranges parameters. The measuring interferometer module was built using polarizing interferometer, which avoids difficulty optical wedge processing when Fizeau interferometer. Regarding problems high low signal-to-noise ratios generated signal, for introduction dispersion crystal causes result traditional method wrong, equation is proposed achieve correct sensor: slow speed problem. This designs acquisition, transmission, system based on digital signal field-programmable gate array, provide hardware platform real-time demodulation. Finally, experiments test resolution, linearity, stability, repeatability were carried out designed system.