Patent ID: 7492983

Claim:
An optical circuit device comprising: an optical circuit; a polarization beam splitter/combiner configured to split an incoming light beam into two polarization beams and to combine the two polarization beams into an outgoing light beam, said polarization beam splitter/combiner including polarization beam splitting/combining circuits each having a polarization beam splitting/combining function, the polarization beam splitting/combining circuits being cascaded at least two stages on the planar substrate; a first optical waveguide and a second optical waveguide configured to connect said optical circuit and said polarization beam splitter/combiner and to receive the two polarization beams independently; and a polarization rotator, arranged on the first optical waveguide, configured to rotate a polarization plane of one of the two polarization beams split by said polarization beam splitter/combiner so as to match a polarization plane of the other of the two polarization beams, said optical circuit, said polarization beam splitter/combiner, said first optical waveguide, said second optical waveguide and said polarization rotator being integrated on a planar substrate.