Optimization of dynamic matched grating filtering demodulation drived by piezoelectric ceramic

An optimized method of dynamic matched grating filtering demodulation system is proposed and experimentally validated, in which PZT's hysteresis effect is eliminated by use of rising sawtooth wave and inverse function of relationship between PZT's voltage and displacement is adopted as the sawtooth wave to correct the PZT's nonlinear effect. Furthermore, a reference fiber Bragg grating is introduced to realized temperature compensation, of which the center wavelength keeps invariable. In the rising stage of the sawtooth wave, the matched grating will match with the reference grating and the sensing grating at different time. The time difference depends on the center wavelength of the sensing grating, and is insensitive to the temperature of the demodulation system. The experimental results indicate that linearity is improved by 2%, the sensitivity error is less than 0.6% of the theoretical result. The relative error caused by temperature changing from 10°C to 60°C is less than 1%.