Highly reliable, small-size fiber-squeezer polarization controller using metal-coated fiber

A fiber-squeezer polarization controller is attractive for use in coherent transmission systems, polarization-shift-keying (PolSK) systems, and optical-sensor systems because of its low insertion loss and low power penalty. For use in a practical system small size and long-term reliability for the controller are required. This paper reports a miniaturized, highly practical fiber-squeezer polarization controller that uses a hermetically sealed optical module and a digital-signal-processor (DSP) controller. Long-term operation of the controller is clarified through a reliability test for the metal-coated fiber used in the controller.