Vertical cavity surface emitting semiconductor laser device

Abstract

A vertical cavity surface emitting semiconductor laser (VCSEL) device has p-type and n-type DBRs sandwiching therebetween a resonant cavity including an active layer. Each the DBRs has a plurality of layer pairs each including a Al x1 Ga 1-x1 As high-reflectivity layer and an Al x2 Ga 1-x2 As low-reflectivity layer and an Al x3 Ga 1-x3 As slope content layer interposed between each of the high-reflectivity layers and adjacent low-reflectivity layer. The slope content layers in the vicinity of the active layer has an Al content x 3 wherein 0 <x 3 ≦0.3 and 0.55≦x 3 <1 and an impurity concentration of 3×10 17 cm −3 or above.

1 . A vertical cavity surface emitting semiconductor laser (VCSEL) device comprising a semiconductor substrate, and a layer structure formed thereon, said layer structure including an active layer, p-type and n-type cladding layers sandwiching therebetween said active layer, p-type and n-type semiconductor multilayer mirrors (DBRs) sandwiching therebetween said p-type and n-type cladding layers and said active layer, and a current confinement layer for injecting therethrough current to said active layer, each of said p-type and n-type DBRs including a plurality of layer pairs each including an Al x1 Ga 1-x1 As high-reflectivity layer (0≦x 1 <1) and an A 1   x2 Ga 1-x 2As low-reflectivity layer (0<x 2 ≦1, and x 1 <x 2 ) and an A 1   x3 Ga 1-x3 As slope content layer (x 1 <x 3 <x 2 ) interposed between each of said high-reflectivity layers and each of said low-reflectivity layers adjacent to said each of said high-reflectivity layers, each of said slope content layers having a slope Al-content profile for Al content x 3 , wherein said slope content layers of said n-type DBR disposed within a distance from said active layer which is equivalent to an effective cavity length of said VCSEL device has an impurity concentration of 3×10 17  cm −3  or above.  
     
     
         2 . The VCSEL device of claim  4 , wherein said slope content layers are doped with at least one element selected from the group consisting of Si, Se, Sn, Te and S.  
     
     
         3 . The VCSEL device of claim  4 , wherein each of said slope content layers of said n-type and p-type DBRs other than said slope content layers of said n-type DBR disposed within said distance from said active layer has an impurity concentration of 5×10 18  cm −3  or below.