Semiconductor laser element

Abstract

To provide a semiconductor laser element having a structure capable of suppressing generation of a kink even in a case where an FFPx is made large, the semiconductor laser element has a ridge structure in which an active layer is provided between a semiconductor layer of one conductivity type and a semiconductor layer of the other conductivity type having a ridge, and window regions that are non-gain regions are provided at both ends thereof, wherein a difference in equivalent refractive index between the ridge and portions on both sides thereof in each of the window regions is larger than a difference in equivalent refractive index between the ridge and portions on both sides thereof in a gain region.

What is claimed is:  
     
         1 . A semiconductor laser element comprising; 
 a first semiconductor layer of one conductivity type,    a second semiconductor layer of the other conductivity type having a ridge,    an active layer provided between said first semiconductor layer and said second semiconductor layer, and    window regions that are non-gain regions at both end portions thereof,    wherein a difference in equivalent refractive index between said ridge and portions on both sides thereof in each of said window regions is larger than a difference in equivalent refractive index between the ridge and portions on both sides thereof in a gain region.    
     
     
         2 . The semiconductor laser element according to  claim 1;   wherein a thickness of the second semiconductor layer remained on the active layer at each side of the ridge in each window region is thinner than a thickness of the second semiconductor layer remained on the active layer at each side of the ridge in the gain region.    
     
     
         3 . The semiconductor laser element according to  claim 2  further comprising buried layers on both sides of said ridge.  
     
     
         4 . The semiconductor laser element according to  claim 1  further comprising buried layers on both sides of said ridge except for window portions.  
     
     
         5 . The semiconductor laser element according to  claim 1  further comprising buried layers on both sides of said ridge, 
 wherein a refractive index of the buried layer in each window region is lower than a refractive index of the buried layer in the gain region.  
 
     
     
         6 . The semiconductor laser element according to  claim 5;   wherein the buried layer of each window region is made of a material having a refractive index lower than the buried layer of the gain region.    
     
     
         7 . The semiconductor laser element according to  claim 5;   wherein the buried layer of each window region has a carrier density higher than the buried layer of the gain region.    
     
     
         8 . A semiconductor laser element comprising; 
 a first semiconductor layer of one conductivity type,    a second semiconductor layer of the other conductivity type having a ridge,    an active layer provided between said first semiconductor layer and said second semiconductor layer, and    window regions that are non-gain regions at both end portions thereof,    wherein buried layers which are made of material capable of absorbing light are formed on both sides of the ridge.