Endless polarization control using two rotatable wave plates with variable birefringence

We present in this article different designs of endless polarization controller based on the concatenation of rotatable wave plates. We show that with these kinds of wave plates, the architecture and the control algorithm of polarization controller are very simple and efficient. The different driving schemes of polarization controller are discussed by studying the limitation of the different possible technologies. Endless polarization control is obtained with two wave plates.