Environmental sealing arrangement for furcated optical fibers

Abstract

An assembly for protecting spliced optical fibers includes: a fiber optic cable comprising at least one optical fiber and a surrounding jacket; at least one elongate tubular member housing the optical fiber, wherein a gap exists between the elongate tubular member and the jacket such that the optical fiber has an exposed region; and a premold block formed of an ultra-low pressure material, the premold block encasing the exposed region of the optical fiber.

That which is claimed is: 
     
         1 . An assembly, comprising:
 a fiber optic cable comprising at least one optical fiber and a surrounding jacket;   at least one elongate tubular member housing the optical fiber;   wherein a gap exists between the elongate tubular member and the jacket such that the optical fiber has an exposed region; and   a premold block formed of an ultra-low pressure material, the premold block encasing the exposed region of the optical fiber.   
     
     
         2 . The assembly defined in  claim 1 , further comprising an overmold layer that covers the premold block. 
     
     
         3 . The assembly defined in  claim 1 , wherein the premold material is a polymeric material selected from the group consisting of polyamide and polyolefin. 
     
     
         4 . The assembly defined in  claim 2 , wherein the premold block includes locating features to locate the premold block in a mold used to create the overmold layer. 
     
     
         5 . The assembly defined in  claim 1 , wherein the at least one optical fiber is a plurality of optical fibers, and the at least one elongate tubular member is a plurality of furcation tubes, each of the furcation tubes housing one or more of the plurality of optical fibers. 
     
     
         6 . An assembly, comprising:
 a fiber optic cable comprising at least one optical fiber and a surrounding jacket;   a elongate tubular member housing the plurality of optical fibers;   wherein a gap exists between the elongate tubular member and the jacket such that the optical fiber has an exposed region; and   an overmold formed of a low pressure material, the overmold encasing the exposed region of the optical fiber.   
     
     
         7 . The assembly defined in  claim 6 , further comprising a heat-shrink tube that overlies the overmold. 
     
     
         8 . The assembly defined in  claim 6 , wherein the low pressure material is a polymeric material selected from the group consisting of polyamide and polyolefin. 
     
     
         9 . The assembly defined in  claim 6 , wherein the at least one optical fiber is a plurality of optical fibers, and wherein the elongate tubular member is a plurality of furcation tubes. 
     
     
         10 . A method for breaking out optical fibers from a fiber optic cable, comprising the steps of:
 (a) stripping a portion of a surrounding jacket from a fiber optic cable comprising at least one optical fiber residing within the jacket;   (b) inserting the optical fiber into an elongate tubular member, wherein a gap exists between the elongate tubular member and the jacket such that the optical fiber has an exposed region; and   (c) molding a premold block over the exposed region of the optical fiber at a molding pressure of between about 0 and 50 psi.   
     
     
         11 . The method defined in  claim 10 , wherein step (c) comprises molding the premold block from an ultra-low pressure material. 
     
     
         12 . The method defined in  claim 11 , wherein the premold material is a polymeric material selected from the group consisting of polyamide and polyolefin. 
     
     
         13 . The method defined in  claim 10 , further comprising the step of molding an overmold layer over the premold block. 
     
     
         14 . The method defined in  claim 13 , wherein the premold block includes locating features that assist with locating the premold block within a mold used to mold the overmold layer. 
     
     
         15 . The method defined in  claim 10 , wherein the at least one optical fibers is a plurality of optical fibers, and wherein the elongate tubular member is a plurality of furcation tubes. 
     
     
         16 . A method for transitioning optical fibers from a fiber optic cable into an elongate tubular member, comprising the steps of:
 (a) stripping a portion of a surrounding jacket from a fiber optic cable comprising at least one optical fiber residing within the jacket;   (b) inserting the optical fiber into an elongate tubular member, wherein a gap exists between the elongate tubular member and the jacket such that the optical fiber has an exposed region; and   (c) molding an overmold over the exposed region of the optical fibers at a molding pressure of between about 50 and 800 psi.   
     
     
         17 . The method defined in  claim 16 , further comprising the step of applying a heat-shrink tube that overlies the overmold. 
     
     
         18 . The method defined in  claim 16 , wherein the low pressure material is a polymeric material selected from the group consisting of polyamide and polyolefin. 
     
     
         19 . The method defined in  claim 16 , wherein the at least one optical fiber is a plurality of optical fibers, and wherein the elongate tubular member is a furcation tube.