Patent ID: 6882670

Claim:
A diode laser comprising: an active layer for generating an optical field; one or more p-type layers on a first side of said active layer; a p-type contact layer for said one or more p-type layers; and a plurality of n-type layers on a second, opposite side of said active layer, one of said plurality of n-type layers being a high refractive index layer having a refractive index higher than said one or more p-type layers and others of said plurality of n-type layers such that the fraction of said optical field in said plurality of n-type lay is larger than the fraction of said optical field in said one or more p-type layers, and one of said plurality of n-type layers being an n-type waveguide layer disposed between the active layer and the high refractive index layer having a lower refractive index than the active layer and the high refractive index layer, wherein the refractive indices and thicknesses of said high refractive index layer and said n-type waveguide layer provide an output laser beam with a divergence of less t an about 28° in a direction transverse to said layers.