Patent ID: 8442088

Claim:
An optical device, comprising: an optical resonator structured to support a whispering gallery mode circulating in a plane of the optical resonator; and a diffractive grating coupler comprising a substrate and a phase-type diffractive grating formed in the substrate, the diffractive grating coupler being located close to the optical resonator to evanescently couple an input optical beam incident at a normal incidence to one side of the substrate of the diffractive grating into the optical resonator located on the other side of the substrate of the diffractive grating, wherein the diffractive grating is structured to suppress diffracted light along the normal incidence and diffract light of the input optical beam into a first diffraction order at a first side of the normal incidence that matches in phase with light in the whispering gallery mode along a first circulating direction and a second diffraction order at a second side of the normal incidence that matches in phase with light in the whispering gallery mode along a second circulating direction opposite to the first circulating direction to create a standing wave in the whispering gallery mode inside the optical resonator.