Patent ID: 7856046
Filing Date: 2010-12-21
Classification: H01S

Abstract:
1. A surface emitting laser diode comprising: a ring-shaped first semiconductor layer including an n-type clad layer; a ring-shaped active layer provided on the first semiconductor layer; and a ring-shaped second semiconductor layer which is provided on the active layer and includes a p-type clad layer and a grating layer including grating units continuously arranged in a circumferential direction, each grating unit including a plurality of regions having different refractive indices and being adjacent to each other in the circumferential direction, wherein an arrangement pitch of the grating units, which is defined as a product of a radius of the second semiconductor layer and an angle between straight lines extending from a center of the second semiconductor layer to adjacent two grating units of the grating units, is equal to 2π/β where β is a propagation coefficient of light which is generated at the active layer and propagates in the grating layer in the circumferential direction.