Multi-port optical switches

Abstract

Optical switches which take multiple incoming optical signals and switch them to multiple output ports to realize multiple working states. For example, in a four by four switch embodiment, twenty-four working states can be selected. These switches rely on magneto-optically or electro-optically switching the beam polarizations from one state to another to rapidly change the light path. An optical signal is spatially split into two polarized beams by a birefringent element. These beams pass through a series of polarization rotation elements and recombine into output fibers, achieving polarization independent operation. A polarization beam splitter may be used as the key element to establish multi-port switching. Light bending devices that allow two fibers to be coupled to the light beams using a single lens may be used to achieve small fiber separation for compactness.