Patent ID: 6996148

Claim:
A semiconductor edge-emitting laser comprising: a) an n-doped region, at least a part of which comprises a photonic band gap crystal including a layered comprising at least one layer, wherein each layer is doped by an n-typed impurity, wherein the layered structure has a periodically modulated refractive index, wherein the periodically modulated refractive index is modulated in a direction perpendicular to a direction of light propagation; b) a defect contiguous with said photonic band gap crystal, comprising: i) a light generating layer that emits light when exposed to an injection current when a forward bias is applied; ii) a first thin tunnel barrier layer for electrons, located on an n-side of the light generating layer, wherein said first thin tunnel barrier layer is formed from a material selected from the group consisting of a weakly-doped n-layer and an undoped layer; iii) a second thin tunnel barrier layer for holes, located on a p-side of the light generating layer, wherein said second thin tunnel barrier layer is formed from a material selected from the group consisting of a weakly-doped p-layer and an undoped layer; iv) two layers sandwiching the first thin tunnel barrier layer; and v) two layers sandwiching the second thin tunnel barrier layer; and c) a p-doped layered structure, comprising at least one layer, wherein each layer is doped by a p-type impurity, and wherein said p-doped layered structure is located on a side of said defect opposite said n-doped region, wherein the p-doped layered structure has a variable refractive index that hinders an extension of a fundamental mode to at least one doped layer within the p-doped layered structure and to a p-contact; wherein the fundamental mode of laser radiation is localized by the defect, while all other modes are extended over the photonic band gap crystal; wherein a total thickness of said photonic band gap crystal and said defect provides a low beam divergence.