Polarization-independent optical circulator for high accuracy Faraday depolarization lidar

A high precision, polarization-independent optical circulator was developed for high accuracy Faraday depolarization lidar. Glan laser prisms and other novel optics were utilized in the circulator optics, resulting in a high extinction ratio of polarization of >30 dB. High accuracy is needed to detect a small rotation angle in the polarization plane of the propagating beam. It is generated by the Faraday effect due to the lightning discharge. The developed circulator delivered high performance of insertion loss and isolation as laser transmitter and echo receiver in the inline lidar optics.