Patent ID: 6275312
Filing Date: 2001-08-14
Classification: G02B,G02F,H04Q

Abstract:
An optical routing switch comprising:a polarization-dependent routing element having:(a) a plurality of prisms joined to form a substantially X-shaped interface between said prisms; and(b) a polarizing beam splitter (PBS) coating in said interface between said prisms, so that said interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second polarization orthogonal to said first polarization along a reflected optical path; anda plurality of input/output (I/O) ports aligned to communicate optical signals along said transmitted and reflected optical paths of said polarization-dependent routing element;wherein at least one of said I/O ports is an input port having:(a) a birefringent element spatially separating an input optical signal into a pair of orthogonally-polarized beams;(b) a polarization rotator rotating the polarization of at least one of the pair of beams so that both beams have substantially the same polarization determined by the control state of the optical routing switch; andwherein at least one of said I/O ports is an output port positioned to receive the pair of beams exiting said polarization-dependent routing element along one of said optical paths, said output port having:(a) a polarization rotator rotating the polarization of at least one of the pair of beams exiting said polarization-dependent routing element so that the beams have substantially orthogonal polarizations; and(b) a birefringent element combining the orthogonally-polarized beams from said polarization rotator of said output port into an output optical signal; andwherein one of the pair of beams propagates from the input port to the output port along a first optical path having a first path length and the other of the pair of beams propagates from the input port to the output port along a second optical path having a second path length substantially similar to the first path length.