In Situ Study on PZT Modulator in Open-Loop FOG

The application characteristic of PZT fiber-optic phase modulator used in open-loop Fiber Optic Gyroscope (FOG) was analyzed theoretically. The open-loop FOG performance defection due to the variation of modulation coefficient and phase delay was studied. Two kinds of in situ measurement methods were designed, with which the temperature characteristic was tested and the temperature model was obtained with the least square polynomial fit method based on the data measured. The study shows that the open-loop FOG phase modulation coefficient K_GP is linear with the temperature variation while the phase delay is quadratic in the experimental temperature range.