Semiconductor optical device and method for producing semiconductor optical device

Abstract

A method for producing a semiconductor optical device includes the steps of bonding a semiconductor chip to an SOI substrate having a waveguide, the semiconductor chip having an optical gain and including a first cladding layer, a core layer, and a second cladding layer that contain III-V group compound semiconductors and are sequentially stacked in this order, forming a covered portion with a first insulating layer on the second cladding layer, etching partway in the thickness direction the second cladding layer exposed from the first insulating film, forming a second insulating film covering from the covered portion to a part of a remaining portion of the second cladding layer, and forming a first tapered portion that is disposed on the waveguide and tapered along the extending direction of the waveguide by etching the core layer and the second cladding layer exposed from the second insulating film.

What is claimed is: 
     
         1 . A semiconductor optical device comprising:
 an SOI substrate having a waveguide; and   a gain region having an optical gain and being provided on the SOI substrate,   the gain region including a first cladding layer, a core layer and a second cladding layer that contain group III-V compound semiconductors and are sequentially stacked in this order,   the gain region being located on the waveguide and having a first tapered portion that is tapered along an extending direction of the waveguide,   the first tapered portion being formed of the core layer and the second cladding layer and having a first portion and a second portion,   the second portion being located at a tip of the first tapered portion, and   the second portion having a thickness smaller than that of the first portion.   
     
     
         2 . The semiconductor optical device according to  claim 1 , wherein
 the second portion is finer and thinner than the first part.   
     
     
         3 . The semiconductor optical device according to  claim 1 , wherein
 the gain region has a second tapered portion,   the second tapered portion is located closer to a tip of the gain region than the first tapered portion and is formed of the first cladding layer.   
     
     
         4 . The semiconductor optical device according to  claim 1 , wherein
 a thickness of the second cladding layer is larger than those of the core layer and the first cladding layer.   
     
     
         5 . The semiconductor optical device according to  claim 1 , wherein
 the second cladding layer contains indium phosphide, and the core layer contains arsenic.   
     
     
         6 . The semiconductor optical device according to  claim 1 , wherein
 the first cladding layer is formed of an n-type indium phosphide,   the second cladding layer is formed of a p-type indium phosphide,   the core layer is formed of an undoped gallium indium arsenide phosphide.