Pigtail-type optical receptacle

Abstract

A pigtail-type optical receptacle includes a tubular ferrule having a through-hole extending in an axial direction, an optical fiber inserted into the through-hole such that part of the optical fiber extends outside the ferrule, a protective member covering the part of the optical fiber extending outside the ferrule, a tubular sleeve mounted on a front end side, outer surface of the ferrule, a holder tubular having holding the rear end side of the ferrule, and a tubular housing covering the ferrule and at least a portion of the sleeve. The ferrule through-hole includes first and second regions, the second region being disposed rearward of the first region, and the housing engaging the outer surface of the holder rearward of the first region.

What is claimed is: 
     
         1 . A pigtail-type optical receptacle, comprising:
 a ferrule having a tubular configuration and having a through-hole extending in an axial direction;   an optical fiber held by the ferrule in a state of being inserted into the through-hole, the optical fiber extending outside the ferrule from a rear end side of the ferrule;   a protective member covering a portion of the optical fiber extending outside the ferrule;   a sleeve having a tubular configuration, engaging an outer surface of the ferrule, and being mounted on a front end side of the ferrule;   a holder having a tubular configuration, engaging the outer surface of the ferrule, and holding the rear end side of the ferrule; and   a housing having a tubular configuration, engaging an outer surface of the holder, and covering the ferrule and at least a portion of the sleeve,   the through-hole of the ferrule including a first region and a second region, a width in an orthogonal direction of the through-hole in the first region corresponding to a width in the orthogonal direction of the optical fiber, the orthogonal direction being orthogonal to the axial direction, the second region being disposed rearward of the first region, the width in the orthogonal direction of the through-hole in the second region widening toward the rear end side of the ferrule,   the housing engaging the outer surface of the holder rearward of the first region.   
     
     
         2 . The receptacle according to  claim 1 , wherein
 the outer surface of the holder includes:
 a first outer perimeter portion held by the housing; and 
 a second outer perimeter portion provided at a front end portion of the holder, the second outer perimeter portion being recessed inward from the first outer perimeter portion, and 
   the first outer perimeter portion is positioned rearward of the first region.   
     
     
         3 . The receptacle according to  claim 1 , wherein
 an inner surface of the housing includes:
 a first inner perimeter portion engaging the outer surface of the holder; and 
 a second inner perimeter portion provided frontward of the first inner perimeter portion, the second inner perimeter portion widening outward from the first inner perimeter portion, and 
   the first inner perimeter portion is positioned rearward of the first region.   
     
     
         4 . The receptacle according to  claim 3 , wherein the second inner perimeter portion is connected to the first inner perimeter portion via a tilted surface or a curved surface.