Patent ID: 8249123

Claim:
A surface emitting laser that oscillates at a wavelength λ, comprising: a multilayer mirror; a lower clad layer; an active layer; an upper clad layer having an effective refractive index n; and a photonic crystal layer whose refractive index changes periodically within a plane parallel to a substrate, wherein the multilayer mirror, the lower clad layer, the active layer, the upper clad layer, and the photonic crystal layer are laminated in this order in a direction perpendicular to the substrate, wherein the photonic crystal layer has a lattice spacing a of λ/(n·sin θ) so as to separate a light having a wavelength λ perpendicularly incident on the photonic crystal layer into at least a transmitted light that forms an angle of 0° with respect to the direction of incidence of the light and a diffracted light incident on the multilayer mirror at an angle θ other than 0° and 90° with respect to the direction of incidence of the light, wherein each layer of the multilayer mirror has a thickness of λ/(4·n i ·cos θ i ), where n i is the refractive index of each layer of the multilayer mirror and θ i is the angle formed by an interface of each layer and the travel direction of the light incident on the multilayer mirror, such that the multilayer mirror has a reflectance with regard to the diffracted light which is higher than reflectance with regard to the transmitted light, wherein a waveguide including the photonic crystal layer and the multilayer mirror has a resonant mode, and wherein the photonic crystal layer diffracts a light of the resonant mode in a direction perpendicular to the substrate.