Design of real-time fast polarization control algorithm

In order to solve the "blind area" problem and control the polarization state of the output optical beam of the polarization controller in real-time, a new polarization control algorithm was proposed by using three cascading waveplates. The complexity of the algorithm was reduced and the speed of the polarization control was improved by combining the coarse control (the step-by-step approach algorithm) and the fine control (the proportional-differential algorithm). Through theoretical analysis and experimental test, the results show that the algorithm does well so that the polarization state of the device's output optical beam is always near the objective state. And the response time of the polarization controller is about 10ms. The polarization controller proposed in the paper has achieved the aim of real-time controlling the output polarization state fast and steadily by adding the feedback structure into the polarization control system.