Patent ID: 9323000
Filing Date: 2016-04-26
CPC Classification: G02B

Claim Text:
1. A waveguide-type polarization beam splitter formed on a substrate, the waveguide-type polarization beam splitter comprising: one or two input optical waveguides; a first multimode interference optical coupler optically coupled to the one or two input optical waveguides and having two inputs and two outputs; a pair of optical waveguide arms optically coupled to the outputs of the first multimode interference optical coupler; a second multimode interference optical coupler optically coupled to the pair of optical waveguide arms and having two inputs and two outputs; and one or two output optical waveguides optically coupled to the outputs of the second multimode interference optical coupler, a quarter wavelength delay is provided in one of the pair of optical waveguide arms, wherein wavelength dependence of the quarter wavelength delay is cancelled out by wavelength dependence of the first and second multimode interference optical couplers, and a groove is provided to extend across the pair of optical waveguide arms, two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, and polarization axes of the respective two quarter wave plates are orthogonal to each other.