Patent ID: 7522647
Filing Date: 2009-04-21
Classification: B82Y,H01S

Abstract:
1. A semiconductor laser comprising: a p-type cladding layer; a second semiconductor layer formed above said p-type cladding layer, and having a band gap smaller than that of said p-type cladding layer; a p-type quantum dot active layer formed above said second semiconductor layer and including: a plurality of layers which have quantum dots having a band gap smaller than that of said second semiconductor layer; and a plurality of p-type or intrinsic third semiconductor layers formed above said layers which have quantum dots, and having a band gap larger than that of the quantum dots, conductivity type of at least one selected from the group consisting of said second semiconductor layer, said quantum dots and said third semiconductor layer being p-type, and at least either one of said quantum dots and said third semiconductor layer having p-type conductivity, wherein each of said layers which have quantum dots and each of said third semiconductor layers are alternated in said p-type quantum dot active layer; and an n-type cladding layer selectively formed on said quantum dot active layer, and having a band gap larger than that of said third semiconductor layer, there being a pin-junction interface between said n-type cladding layer and said quantum dot active layer, wherein an area of said pin-junction interface is smaller than an area of an interface between said second semiconductor layer and said quantum dot active layer.