Dynamic parameter measurement and efficient drive matching method for PEM

In order to improve the driving efficiency of photoelastic modulator (PEM), a method of impedance matching parameter calculation based on dynamic parameter measurement of PEM was proposed. The relationship between PEM modulation amplitude and driving voltage was analyzed theoretically, and the equivalent circuit model of PEM and its resonance matching network were established. On this basis, the relationship between PEM resonant driving voltage and various parameters was derived, and the measurement system and verification method for the dynamic test of PEM were also designed. Theoretical simulation and experimental comparison of various characteristic curves were conducted on a PEM with a resonant frequency of 44.822 kHz, which verified the reliability of the dynamic measurement system, and the PEM optimal matching parameters were obtained by numerical simulation. Near the optimal matching parameters, the different matching parameters were selected to measure the actual resonance driving voltage. The correlation between the measurement results and the simulation curve reaches 0.996 4, and the change trend is basically consistent before 10 μF. The peak resonance driving voltage reaches 510 V, which is better than other driving matching methods and close to the theoretical maximum, and the relative error is less than 1.16%. The optimal matching parameter calculated by the PEM equivalent dynamic parameters can achieve the maximum driving efficiency of PEM.