Optical semiconductor module

Abstract

An optical semiconductor module includes an optical semiconductor element; an optical fiber optically coupled with the semiconductor element; a base having an upper surface and a lower surface; and a package. The package has a bottom plate on which the base is mounted, a front wall having a hole through which the optical fiber is inserted, and a rear wall opposite to the front wall. The optical fiber and the optical semiconductor element are mounted on the upper surface. The base has a rear face formed on an end portion opposite to the front wall, and the rear face is positioned above the lower surface of the base.

What is claimed is:  
     
         1 . An optical semiconductor module, comprising: 
 an optical semiconductor element;    an optical fiber optically coupled with the semiconductor element;    a base having an upper surface and a lower surface, the optical fiber and the optical semiconductor element being mounted on the upper surface; and    a package having 
 a bottom plate on which the base is directly mounted,  
 a front wall having a hole through which the optical fiber is inserted, and  
 a rear wall opposite to the front wall,  
   wherein the base has a rear face formed on an end portion opposite to the front wall, the rear face being positioned above the lower surface.    
     
     
         2 . The optical semiconductor module according to  claim 1 , wherein the rear face is tapered such that the rear face approaches to the upper surface as approaching to the rear wall of the package.  
     
     
         3 . The optical semiconductor module according to  claim 1 , wherein the rear face is curved such that the rear face approaches to the upper surface as approaching to the rear wall of the package.  
     
     
         4 . The optical semiconductor module according to  claim 1 , wherein the rear face constitutes a step.  
     
     
         5 . The optical semiconductor module according to  claim 1 , wherein a diameter of the hole in the front wall is larger than a diameter of the hole at a position away from the front wall.  
     
     
         6 . The optical semiconductor module according to  claim 1 , wherein the package is any one of a butterfly package and a dual-in-line package.  
     
     
         7 . The optical semiconductor module according to  claim 1 , wherein at least one of sides of a main body of the package has a length not larger than 16 millimeter.  
     
     
         8 . An optical semiconductor module, comprising: 
 an optical semiconductor element;    an optical fiber optically coupled with the semiconductor element;    a base having an upper surface and a lower surface, the optical fiber and the optical semiconductor element being mounted on the upper surface;    a package having 
 a bottom plate on which the base is directly mounted, and  
 a front wall having a hole through which the optical fiber is inserted; and  
   a lid having a first portion disposed above the base and a second portion facing the hole, the first portion and the second portion of the lid being combined with each other to cover the package.    
     
     
         9 . The optical semiconductor module according to  claim 8 , wherein the package further has a rear wall opposite to the front wall, the rear wall being combined with the second portion of the lid.  
     
     
         10 . The optical semiconductor module according to  claim 9 , wherein the base has a rear face formed on an end portion opposite to the front wall, the rear face being positioned above the lower surface.  
     
     
         11 . The optical semiconductor module according to  claim 8 , wherein the rear face is tapered such that the rear face approaches to the upper surface as approaching to the rear wall of the package.  
     
     
         12 . The optical semiconductor module according to  claim 8 , wherein the rear face is curved such that the rear face approaches to the upper surface as approaching to the rear wall of the package.  
     
     
         13 . The optical semiconductor module according to  claim 8 , wherein the rear face constitutes a step.  
     
     
         14 . The optical semiconductor module according to  claim 8 , wherein a diameter of the hole in the front wall is larger than a diameter of the hole at a position away from the front wall.  
     
     
         15 . The optical semiconductor module according to  claim 8 , wherein the package is any one of a butterfly package and a dual-in-line package.  
     
     
         16 . The optical semiconductor module according to  claim 8 , wherein at least one of sides of a main body of the package has a length not larger than 16 millimeter.  
     
     
         17 . An optical semiconductor module, comprising: 
 an optical semiconductor element;    an optical fiber optically coupled with the semiconductor element;    a base having an upper surface and a lower surface, the optical fiber and the optical semiconductor element being mounted on the upper surface;    a package having 
 a bottom plate on which the base is mounted, and  
 a front wall having a hole through which the optical fiber is inserted; and  
   a lid having a cover portion disposed above the base,    wherein at least one of the base and the package has a means for preventing any one of 
 a reduction in an optical coupling efficiency between the optical fiber and the semiconductor element; and  
 a breakage of the optical fiber during assembling the semiconductor module.  
   
     
     
         18 . The optical semiconductor module according to  claim 17 , wherein the means includes any one of 
 a rear face that is formed on an end portion opposite to the front wall such that the rear face is positioned above the lower surface; and    a wall portion facing the hole, and combined with the cover portion to cover the package.