Patent ID: 6707834
Filing Date: 2004-03-16
Classification: H01S

Abstract:
A semiconductor laser device comprising:an active layer; a first-conductivity type cladding layer and a second-conductivity type cladding layer sandwiching the active layer therebetween; a second-conductivity type contact layer disposed above the second-conductivity type cladding layer and having a bandgap different from a bandgap of the second-conductivity type cladding layer; and a second-conductivity type intermediate bandgap layer disposed between the second-conductivity type cladding layer and the second-conductivity type contact layer and having an intermediate bandgap between the bandgaps of the second-conductivity type cladding layer and the second-conductivity type contact layer, wherein said second-conductivity type contact layer comprises at least a first contact layer, an intermediate second contact layer and a third contact layer stacked in this order and the second contact layer has an impurity density lower than impurity densities of the first and third contact layers.