Patent ID: 7558307
Filing Date: 2009-07-07
Classification: G11B,H01L,H01S

Abstract:
1. A ridge waveguide semiconductor laser device having at least an active layer and a semiconductor layer group of a second conductive type on which a ridge portion is formed on a substrate of a first conductive type, comprising: an upper electrode which is formed on the semiconductor layer group of the second conductive type and put in contact with at least one of a side surface of the ridge portion of the semiconductor layer group of the second conductive type and a surface located in the neighborhood of the ridge portion in a region of the semiconductor layer group of the second conductive type except for the ridge portion, the upper electrode having a high refractive index layer and a low refractive index layer formed successively from a side put in contact with the semiconductor layer group of the second conductive type the high refractive index layer having a refractive index of not lower than 2.5 with respect to a wavelength band of emission laser light and a thickness of not greater than 75 nm, and the low refractive index layer having a refractive index of not higher than 1.0.