Optical fiber connector, ferrule used therefor and method for manufacturing ferrule

Abstract

Electroforming is performed in an electroforming bath with a cathode of a metal wire member immersed in an electroforming solution to electrodeposit nickel around the aluminum alloy wire member. The aluminum alloy wire member is removed by dissolution with an alkaline solution from an obtained nickel electroformed product. Accordingly, a nickel cylinder is obtained, which has a through-hole formed corresponding to the wire member. The cylinder is cut into those having a predetermined length. The outer circumference is subjected to cutting based on the through-hole to obtain a ferrule. The inner diameter accuracy of the through-hole of the ferrule is determined by the outer diameter accuracy of the wire member. Therefore, it is unnecessary to perform polishing for the through-hole. The highly accurate ferrule is obtained in accordance with the simple process at low cost. The PC polishing for the ferrule for effecting PC junction of optical fibers is extremely easy, because the ferrule is made of metal. Thus, it is possible to provide a high performance optical fiber connector.

What is claimed is:  
     
         1 . A method for producing a ferrule which is used for connecting optical fibers, the method comprising: 
 depositing a metal by means of electroforming around at least one wire member to produce a rod-shaped electroformed product; and    removing the wire member from the electroformed product.    
     
     
         2 . The method for producing the ferrule according to  claim 1 , wherein the wire member has a circular cross section and a diameter of the wire member is not more than 0.13 mm.  
     
     
         3 . The method for producing the ferrule according to  claim 1 , further comprising cutting an outer circumference of the electroformed product about a center of a through-hole formed by removing the wire member from the electroformed product.  
     
     
         4 . The method for producing the ferrule according to  claim 1 , wherein the wire member is a wire member made of metal or plastic.  
     
     
         5 . The method for producing the ferrule according to  claim 1 , wherein that the wire member is removed from the electroformed product by dissolving the wire member with an alkaline or acidic solution after the electroforming.  
     
     
         6 . The method for producing the ferrule according to  claim 5 , wherein the wire member is made of aluminum or alloy thereof.  
     
     
         7 . The method for producing the ferrule according to  claim 1 , wherein a mold release treatment is applied to the wire member before the electroforming, and the wire member is removed from the electroformed product by extracting the wire member from the electroformed product after the electroforming.  
     
     
         8 . The method for producing the ferrule according to  claim 7 , wherein the wire member is made of iron or alloy thereof.  
     
     
         9 . The method for producing the ferrule according to  claim 1 , wherein a mold release treatment is applied to the wire member before the electroforming, and the wire member is removed from the electroformed product by extruding the wire member from the electroformed product after the electroforming.  
     
     
         10 . The method for producing the ferrule according to  claim 1 , wherein the at least one wire member is two wire members which are arranged to be separated from each other by a predetermined distance.  
     
     
         11 . The method for producing the ferrule according to  claim 10 , wherein the two wire members are positioned so that a pin having a predetermined size is interposed thereby.  
     
     
         12 . The method for producing the ferrule according to  claim 1 , wherein the at least one wire member is three wire members which are arranged to be separated from each other by an identical distance.  
     
     
         13 . The method for producing the ferrule according to  claim 1 , wherein the metal is one selected from the group consisting of aluminum, nickel, iron, copper, cobalt, tungsten, and alloys thereof.  
     
     
         14 . The method for producing the ferrule according to  claim 1 , wherein the metal is nickel.  
     
     
         15 . The method for producing the ferrule according to  claim 1 , further comprising cutting the electroformed product into those having a predetermined length.  
     
     
         16 . A metal ferrule produced in accordance with the method as defined in  claim 1 .  
     
     
         17 . The metal ferrule according to  claim 16 , wherein the ferrule has a columnar hollow section which penetrates in a longitudinal direction of the ferrule, the ferrule has, at its first end, a first opening which has the same diameter as that of the hollow section, and the ferrule has, at its second end, a second opening which has a diameter larger than the diameter of the hollow section.  
     
     
         18 . The metal ferrule according to  claim 17 , wherein the hollow section includes a first hollow section, a second hollow section which has a diameter larger than that of the first hollow section, and a third hollow section having a tapered configuration which connects the first hollow section and the second hollow section.  
     
     
         19 . The metal ferrule according to  claim 18 , wherein a coated portion of an optical fiber is accommodated in the second hollow section, and a clad of the optical fiber is accommodated in the first hollow section.  
     
     
         20 . A ferrule used for connecting optical fibers, wherein the ferrule is integrally formed of only a metal material.  
     
     
         21 . The ferrule according to  claim 20 , which is produced by electroforming.  
     
     
         22 . The ferrule according to  claim 20 , wherein the metal is one selected from the group consisting of aluminum, nickel, iron, copper, cobalt, tungsten, and alloys thereof.  
     
     
         23 . The ferrule according to  claim 20 , wherein a plurality of hollow sections for allowing the optical fiber to pass therethrough are formed.  
     
     
         24 . The ferrule according to  claim 20 , wherein holes for allowing the optical fiber to penetrate therethrough have a tapered configuration at both ends of the ferrule, and the ferrule is used for a mechanical splice.  
     
     
         25 . The ferrule according to  claim 20 , wherein the ferrule has a columnar hollow section which penetrates in a longitudinal direction of the ferrule, the ferrule has, at its first end, a first opening which has the same diameter as that of the hollow section, and the ferrule has, at its second end, a second opening which has a diameter larger than the diameter of the hollow section.  
     
     
         26 . The ferrule according to  claim 25 , wherein the hollow section includes a first hollow section, a second hollow section which has a diameter larger than that of the first hollow section, and a third hollow section having a tapered configuration which connects the first hollow section and the second hollow section.  
     
     
         27 . The metal ferrule according to  claim 26 , wherein a coated portion of the optical fiber is accommodated in the second hollow section, and a clad of the optical fiber is accommodated in the first hollow section.  
     
     
         28 . The ferrule according to  claim 20 , which is used for an optical fiber connector.  
     
     
         29 . An optical fiber connector for connecting optical fibers, comprising: 
 a ferrule integrally formed of only a metal material; and    a housing for accommodating the ferrule.    
     
     
         30 . The optical fiber connector according to  claim 29 , wherein the ferrule is formed by electroforming.  
     
     
         31 . The optical fiber connector according to  claim 29 , further comprising a holder for holding the ferrule and positioning the ferrule in a rotational direction in the housing.  
     
     
         32 . The optical fiber connector according to  claim 29 , further comprising, in the ferrule, an optical fiber which is shorter than a length of the ferrule, wherein a tip of the optical fiber and a tip of the ferrule has been PC polished.  
     
     
         33 . The optical fiber connector according to  claim 29 , wherein the housing is a plug.  
     
     
         34 . The optical fiber connector according to  claim 29 , further comprising a sleeve for aligning the ferrule.  
     
     
         35 . The optical fiber connector according to  claim 29 , wherein the housing is a jack.  
     
     
         36 . The optical fiber connector according to  claim 33 , further comprising an adapter for making detachable connection to the plug, the adapter having a sleeve for aligning the ferrule.  
     
     
         37 . The optical fiber connector according to claim  29 , further comprising an optical fiber cable, wherein a tip of an optical fiber of the optical fiber cable is located at a tip of the ferrule.  
     
     
         38 . The optical fiber connector according to  claim 37 , wherein the tip of the optical fiber and the tip of the ferrule have been simultaneously polished.  
     
     
         39 . The optical fiber connector according to  claim 38 , wherein the polishing is flat polishing or PC polishing.  
     
     
         40 . A wire member-supporting apparatus for being used when a ferrule having multiple cores for connecting optical fibers is produced by means of electroforming, the apparatus comprising: 
 a base plate;    a pair of first positioning projections provided mutually opposingly on the base plate, each of the first projections having an identical width; and    two wire members stretched in parallel to one another with the pair of first positioning projections interposed therebetween.    
     
     
         41 . The apparatus according to  claim 40 , wherein the two wire members are positioned by the aid of the projections, and a spacing distance between the two wire members is defined thereby.  
     
     
         42 . The apparatus according to  claim 41 , wherein the two wire members are connected at their ends respectively to form one wire member.  
     
     
         43 . The apparatus according to  claim 40 , wherein the projection is a pin provided on the base plate.  
     
     
         44 . The apparatus according to  claim 40 , further comprising a plurality of guide pins for winding the wire member therearound in order to maintain tension of the wire member.  
     
     
         45 . The apparatus according to  claim 40 , further comprising: 
 a pair of second positioning projections provided mutually opposingly on the base plate, each of the second projections having an identical width; and    two wire members stretched in parallel to one another with the pair of second positioning projections interposed therebetween, wherein:    the wire members stretched in parallel to one another with the first projections interposed therebetween are mutually parallel to the wire members stretched in parallel to one another with the second projections interposed therebetween, and the respective adjoining wire members are separated from each other by an identical distance.