Two-dimensional photonic crystal laser and method of producing the same

Abstract

A two-dimensional photonic crystal laser according to the present invention includes a two-dimensional photonic crystal layer 15 having a base body made of Al α Ga 1-α As (0<α<1) or (Al β Ga 1-β ) γ In 1-γ P (0<=β<1, 0<γ<1) with modified refractive index areas (air holes) 151 periodically arranged therein and an epitaxial growth layer 16 created on the two-dimensional photonic crystal layer 15 by an epitaxial method. Since Al α Ga 1-α As and (Al β Ga 1-β ) γ In 1-γ P are solid even at high temperatures, the air holes 151 will not be deformed in the process of creating the epitaxial growth layer 16 , so that the performance of the two-dimensional photonic crystal layer 15 as a resonator can be maintained at high levels.

1 . A method of producing a two-dimensional photonic crystal laser, comprising:
 a) a base-body layer creation process for creating a base-body layer having a same crystal structure as Al x Ga 1-x As (0.4<=x<1);   b) an air-hole formation process for periodically forming air holes in the base-body layer, each of the air holes having a maximum width d in planer shape and a depth h, where d satisfies d<=200 nm and a depth-to-width ratio h/d satisfies 1.3<=h/d<=5; and   c) an epitaxial-layer creation process for creating a layer made of the aforementioned Al x Ga 1-x As on the base-body layer and the air holes by an epitaxial method.   
     
     
         2 . The method of producing a two-dimensional photonic crystal laser according to  claim 1 , wherein the base-body layer is a layer created by epitaxially growing Al α Ga 1-α As (0<α<1) or (Al β Ga 1-β ) γ In 1-γ P (0<=β<1, 0<γ<1). 
     
     
         3 . The method of producing a two-dimensional photonic crystal laser according to  claim 1 , wherein the base-body layer has a multi-layer structure having a plurality of layers. 
     
     
         4 . The method of producing a two-dimensional photonic crystal laser according to  claim 1 , wherein a process for forming a crystal-growth inhibiting film for inhibiting a crystal growth of the aforementioned Al x Ga 1-x As on at least a portion of an inner surface of the air holes is included between the air-hole formation process and the epitaxial-layer creation process. 
     
     
         5 . The method of producing a two-dimensional photonic crystal laser according to  claim 4 , wherein the crystal-growth inhibiting film is made of a material selected from a group of SiO 2 , Si 3 N 4 , ZnO and ZrO 2 . 
     
     
         6 . The method of producing a two-dimensional photonic crystal laser according to  claim 1 , wherein the air hole has an elliptic planer shape with a major diameter being directed in a growth direction of Al x Ga 1-x As within a plane parallel to the base-body layer. 
     
     
         7 . The method of producing a two-dimensional photonic crystal laser according to  claim 1 , wherein a planer shape of the air hole is a polygon with a groove-like projected portion extending outward from each vertex of the polygon. 
     
     
         8 . A method of producing a two-dimensional photonic crystal, comprising:
 a) a base-body layer creation process for creating a base-body layer having a same crystal structure as Al x Ga 1-x As (0<x<=0.8);   b) an air-hole formation process for periodically forming air holes in the base-body layer, each of the air holes having a maximum width d in planer shape and a depth h, where d satisfies d<=200 nm and a depth-to-width ratio h/d satisfies 0.1<=h/d<=1.2;   c) a modified refractive index area formation process for forming, by an epitaxial method, modified refractive index areas made of the aforementioned Al x Ga 1-x As in the air holes; and   d) an epitaxial-layer creation process for creating, by the aforementioned epitaxial method, a layer made of Al y Ga 1-y As (0<=y<=1) on the base-body layer having the modified refractive index areas formed therein.   
     
     
         9 . The method of producing a two-dimensional photonic crystal laser according to  claim 8 , wherein x equals y. 
     
     
         10 . The method of producing a two-dimensional photonic crystal laser according to  claim 9 , wherein the modified refractive index area formation process and the epitaxial-layer creation process are simultaneously performed. 
     
     
         11 . The method of producing a two-dimensional photonic crystal laser according to  claim 8 , wherein a process for forming a crystal-growth inhibiting film for inhibiting an epitaxial growth of the aforementioned Al x Ga 1-x As on the base-body layer is included between the base-body layer creation process and the modified refractive index area formation process. 
     
     
         12 . The method of producing a two-dimensional photonic crystal laser according to  claim 11 , wherein the crystal-growth inhibiting film is made of a material selected from a group of SiO 2 , Si 3 N 4 , ZnO and ZrO 2 . 
     
     
         13 . The method of producing a two-dimensional photonic crystal laser according to  claim 8 , wherein the base-body layer is a layer created by epitaxially growing Al α Ga 1-α As (0<α<1) or (Al β Ga 1-β ) γ In 1-γ P (0<=β<1, 0<γ<1). 
     
     
         14 . The method of producing a two-dimensional photonic crystal laser according to  claim 8 , wherein the base-body layer has a multi-layer structure having a plurality of layers. 
     
     
         15 . A method of producing a two-dimensional photonic crystal laser, comprising:
 a) a modified refractive index area formation process for periodically forming columnar modified refractive index areas on an epitaxial-growth substrate layer having a same crystal structure as Al x Ga 1-x As (0<x<=0.65), the modified refractive index areas being made of a material whose refractive index differs from that of the aforementioned Al x Ga 1-x As;   b) a base-body creation process for creating, by an epitaxial method, a base body made of the aforementioned Al x Ga 1-x As in a space between the modified refractive index areas; and   c) an epitaxial-layer creation process for creating, by the aforementioned epitaxial method, a layer made of Al y Ga 1-y As (0<=y<=1) on a layer in which the modified refractive index areas and the base body have been formed.   
     
     
         16 . The method of producing a two-dimensional photonic crystal laser according to  claim 15 , wherein the modified refractive index areas are formed by etching the epitaxial-growth substrate layer in such a manner that a portion thereof in a thickness direction and the modified refractive index areas are left. 
     
     
         17 . The method of producing a two-dimensional photonic crystal laser according to  claim 15 , wherein x equals y. 
     
     
         18 . The method of producing a two-dimensional photonic crystal laser according to  claim 17 , wherein the base-body creation process and the epitaxial-layer creation process are simultaneously performed. 
     
     
         19 . The method of producing a two-dimensional photonic crystal laser according to  claim 15 , wherein a process for forming a crystal-growth inhibiting film for inhibiting an epitaxial growth of the aforementioned Al x Ga 1-x As on a top face of the modified refractive index areas is included between the modified refractive index area formation process and the base-body layer creation process. 
     
     
         20 . The method of producing a two-dimensional photonic crystal laser according to  claim 19 , wherein the crystal-growth inhibiting film is made of a material selected from a group of SiO 2 , Si 3 N 4 , ZnO and ZrO 2 . 
     
     
         21 . The method of producing a two-dimensional photonic crystal laser according to  claim 15 , wherein the modified refractive index areas are made of a material selected from a group of SiO 2 , Si 3 N 4 , ZnO and ZrO 2 . 
     
     
         22 . The method of producing a two-dimensional photonic crystal laser according to  claim 15 , wherein the epitaxial-growth substrate layer is a layer created by epitaxially growing Al α Ga 1-α As (0<=α<=1) or (Al β Ga 1-β ) γ In 1-γ P (0<=β<=1, 0<=γ<=1).