Fiber Polarization Rotation Switch based on Modulation Instability.

We demonstrate an active fiber polarization rotation switch based on modulation instability operating near 1.5microns, exhibiting contrast ratios up to 40:1 and small signal gains up to 40dB. Modulation instability induces rotation of an initially nulled polarization through the wavelength dependent beat length of the fiber. Since the switch uses simple, non- polarization-maintaining, single-mode fiber, long lengths of fiber can be used to reduce the pump requirements.