Automatic positioning of optical axis of wave-plate in a laser feedback birefringence measurement system

In order to solve the problem of complex structure, time-consuming and unstable state in the process of adjusting optical elements in a traditional birefringence measurement system, the duty cycles of o light and e light at low levels in polarization flipping curves were calculated.The function of automatic rotating wave-plate was added in a birefringence measurement system optimized with high efficiency.The system can automatically adjust the direction of fast axis of the wave-plate aligned with the intrinsic polarization direction of laser and reduce the measurement error that may be introduced when judging the fast axis of wave-plate artificially.After many measurements, the results show that the maximum deviation of wave-plate phase delay is 0.65°, and the standard deviation is reduced by 28%.The measurement accuracy and stability of birefringence measurement systems have met the requirements of industrial production.