Polarization stabilizer using liquid crystal rotatable waveplates

In standard single-mode fiber (SMF) transmission systems, a polarization stabilizer is useful for optimizing the performance of polarization dependent systems or devices. We have proposed and developed a polarization stabilizer which employs liquid crystal (LC) rotatable waveplates. It has a simple configuration, no moving parts, and endless-control characteristic. High polarization stability was confirmed under various state of polarization (SOP) fluctuations. The maximum response speed of the polarization stabilizer is about 900/spl deg//s, but this can be increased by improving the controller. We applied the polarization stabilizer to a semiconductor optical amplifier (SOA) having polarization dependence, and achieved good gain stabilization.