Patent ID: 6813399
Filing Date: 2004-11-02
Classification: B82Y,G02B,G02F

Abstract:
An optical device comprising:a first optical member separating an incident light of wavelength &lgr; into a TE wave and a TM wave; and an optical input portion, which inputs the incident light into the first optical member; wherein the first optical member has a periodically changing refractive index; wherein an angle defined by a first reciprocal lattice vector &agr;1 and a second reciprocal lattice vector &agr;2 of the first optical member at the wavelength &lgr; is not larger than 90Â°; wherein, in the direction of the first reciprocal lattice vector &agr;1, the wave number of the TE wave is larger than the wave number of the TM wave; wherein, in the direction of the second reciprocal lattice vector &agr;2, the wave number of the TE wave is smaller than the wave number of the TM wave; wherein the optical input portion inputs the incident light in a direction that is parallel to a plane P12 including the first reciprocal lattice vector &agr;1 and the second reciprocal lattice vector &agr;2; and wherein a size of the wave number of the TE wave and the wave number of the TM wave alternate in the direction of the first reciprocal lattice vector &agr;1 and in the direction of the second reciprocal lattice vector &agr;2.