Patent ID: 8401350

Claim:
An optical resonator comprising: N individual optical waveguide paths of line segment shape disposed in a common flat-plane so as to intersect at a single intersection region, wherein N is an integer of 2 or more; curved optical waveguide paths connecting respective portions of the optical waveguide paths that extend towards the outside from the intersection region, wherein for a first to a 2N th optical waveguide path portions in a clockwise direction, connection is made between end portions at the opposite side to the intersection region of the (2i−1) th to 2i th optical waveguide path portions, wherein i is an integer of 1 to N; and an optical coupler that couples light input or output perpendicular to the flat-plane with the optical waveguide paths, the optical coupler being formed in a region containing the intersection region where the optical waveguide paths are connected, wherein light is inputted into an input end of the optical coupler, passes through the curved optical waveguide paths, and then is outputted from an output end of the optical coupler, the input end and the output end being the same.