Complete polarization controller based on magneto-optic crystals and fixed quarter wave plates.

We propose and demonstrate a polarization controller, which is a concatenation of three Faraday rotators based on magneto-optic crystals separated by two fixed quarter wave plates. Comparing with former schemes, this polarization controller is fast, accurate and stable because it is completely driven by electric signals and has no mechanically moving parts.It is simple-structured and low-cost. Moreover, it is programmable to convert an arbitrary state of polarization (SOP) from the input to any designated SOP at the output. It can also be used as a polarization scrambler. It has potential applications in the research of the polarization dependence of optical communication systems or the compensation of polarization mode dispersion (PMD), etc.