Optical fiber assembly and manufacturing method for the same

• US 5,621,835 A
• Filed: 08/08/1995
• Issued: 04/15/1997
• Est. Priority Date: 05/20/1994
• Status: Expired due to Term

• Current Assignee: Seikoh Giken Company Limited
• Original Assignee: Seikoh Giken Company Limited
• Inventors: Takahashi, Mitsuo, Yamada, Kunio
• Primary Examiner(s): Healy, Brian
• Application Number:
  US08/512,411
• Time in Patent Office: 616 Days
• Field of Search: 385/76, 385/77, 385/78, 385/80, 385/84, 385/85, 385/81, 385/86, 385/87, 385/139
• US Class Current: 385/78
• CPC Class Codes: G02B 6/3861 Adhesive bonding adhesives in general C09J
• CPC Class Codes: G02B 6/3889 using encapsulation for protection, e.g. adhesive, molding or casting resin

Abstract

An optical fiber assembly which can be used without deterioration in the performance thereof even when it is used under a severe environmental condition wherein temperature frequently changes over a wide temperature range. The structure of an optical fiber assembly in accordance with the invention may be applied to an optical fiber connector plug and the like. The optical fiber connector plug is constituted by an optical fiber having an end with a protective sheath thereof removed, a ferrule of a support for fixing of the optical fiber, a thin-wall metal pipe which receives the protective sheath on the optical fiber and fixes it by crimping a plurality of places thereof, and a metal supporting sleeve with a flange which is provided as an integral part of the ferrule and which supports the thin-wall metal pipe. The optical fiber and the thin-wall metal pipe are fixed to the ferrule and the metal supporting sleeve, respectively, at the same time by gluing with thermosetting resin. The physical properties such as the hardness of the protective sheath of the optical fiber assembly change in a reversible manner between the upper and lower extremes of the environment wherein the optical fiber assembly is used; however, the problem of slipping out (pistoning) observed in a conventional optical fiber assembly is reliably prevented.

Claims

1. An optical fiber assembly comprising:

an optical fiber having a protective sheath at a distal end thereof, said optical fiber projecting from said sheath;

a pipe surrounding said protective sheath adjacent the distal end of said optical fiber, said pipe being secured to said sheath by crimping;

a ferrule surrounding the distal end of said optical fiber;

a supporting sleeve having a stepped portion at one end thereof for receiving an end of said ferrule, said supporting sleeve surrounding said pipe and said ferrule; and

a thermosetting resin for adhering said optical fiber and said pipe to said ferrule and said supporting sleeve.

2. The optical fiber assembly according to claim 1, wherein said sheath is butted against said ferrule.

3. The optical fiber assembly according to claim 1, wherein said ferrule is made of a ceramic material, and said supporting sleeve is made of metal.

4. An optical fiber assembly comprising:

an optical fiber having a protective sheath at a distal end thereof, said optical fiber projecting from said sheath;

a pipe having a plurality of symmetrically located deformed portions extending along an axis thereof, said pipe surrounding said protective sheath adjacent the distal end of said optical fiber and being secured to said sheath by being symmetrically crimped at said deformed portions;

a ferrule surrounding the distal end of said optical fiber;

a supporting sleeve having a stepped portion at one end thereof for receiving an end of said ferrule, said supporting sleeve surrounding said pipe and said ferrule; and

a thermosetting resin for adhering said optical fiber and said pipe to said ferrule and said supporting sleeve.

5. A method of manufacturing an optical fiber assembly including a ferrule, a supporting sleeve, an optical fiber having a protective sheath at a distal end thereof, and a metal pipe, said method comprising the steps of:

inserting an end of the ferrule into an end of the supporting sleeve;

exposing a portion of said optical fiber so that it projects from said sheath;

inserting the distal end of the optical fiber into the metal pipe whereby the pipe surrounds the protective sheath;

deforming the metal pipe by crimping thereby securing it to the sheath, projections on an internal wall of the pipe resulting from said deformation biting into the sheath;

applying a thermosetting adhesive agent to the ferrule;

inserting the exposed portion of the optical fiber into an opening in the ferrule and the metal pipe into the supporting sleeve; and

heating the resulting assembly thereby fixing with the adhesive agent the optical fiber to the ferrule and the metal pipe to the supporting sleeve.

6. The method according to claim 5, wherein said crimping exerts a pressure between 200 to 400 grams per millimeter.