Abstract: The present invention provides improved optical switches in which only a spatial beam shifting of a small free space offset is required to direct optical pathways between plural fiber ports. This is achieved by spacing two fibers closely and collimating their beams with one imaging lens for compactness. Advantageously, the inventive switches incorporate beam correcting devices to render the beam propagations parallel, allowing light beams to be efficiently coupled into two fibers that share a single lens with substantially improved stability.
Abstract: The present invention provides improved optical switches in which no mechanical movement is required to direct optical pathways between plural fiber ports. Advantageously, the inventive switches incorporate two-stage polarization rotation to improve isolation depth, as well as temperature and wavelength independence. The inventive switches also incorporate light bending devices to allow two fibers to be coupled to the light beams using a single lens achieving small beam separation for compactness. In the inventive switch, an optical signal is spatially split into two polarized beams by a birefringent element, which passes through a polarization rotation device that comprises waveplates, walk-off elements, and electrically controllable polarization rotators, and recombine into an output fiber, achieving polarization independent operation.