Armored fiber optic assemblies and methods of forming fiber optic assemblies

Abstract

Cables have dielectric armors with armor profiles that provide additional crush and impact resistance for the optical fibers and/or fiber optic assembly therein, while retaining flexibility to aid during installation. The armored cables recover substantially from deformation caused by crush loads.

We claim: 
     
         1 . A method of forming an armored fiber optic assembly, comprising:
 providing a fiber optic assembly comprising at least one optical fiber;   extruding an inner layer of a dielectric armor around the fiber optic assembly, wherein extruding the inner layer comprises diverting a flow of an inner extrusion material with a first profiling feature to form a spiral strip; and   extruding an outer layer of the dielectric armor around the inner layer from an outer extrusion material that is less rigid than the inner extrusion material, wherein the outer layer becomes at least partially bonded to the inner layer.   
     
     
         2 . The method of  claim 1 , wherein diverting the flow of extrusion material using the first profiling feature includes relative rotational motion between the profiling feature and the fiber optic assembly and wherein diverting the flow of the inner extrusion material occurs as the fiber optic assembly passes through an extrusion crosshead. 
     
     
         3 . The method of  claim 2 , the profiling feature being a rotating element at an extrusion crosshead. 
     
     
         4 . The method of  claim 2 , the inner layer being a polyvinyl chloride (PVC) and the outer layer being a PVC. 
     
     
         5 . The method of  claim 2 , wherein the outer layer has a continuous annular cross-section. 
     
     
         6 . The method of  claim 5 , wherein the armor profile is formed to undulate along a length of the fiber optic assembly. 
     
     
         7 . The method of  claim 5 , wherein the armor profile is formed with a band thickness and a web thickness, the band thickness being between 0.5 millimeters and five millimeters. 
     
     
         8 . The method of  claim 7 , wherein the web thickness is greater than or equal to 0.1 times the band thickness, and wherein the armor profile has a pitch between 5 millimeters and 30 millimeters. 
     
     
         9 . The method of  claim 2 , wherein the profiling feature is turned by a motor. 
     
     
         10 . The method of  claim 2 , wherein the fiber optic assembly comprises a cable jacket and a plurality of optical fibers. 
     
     
         11 . A method of forming an armored fiber optic assembly, comprising:
 providing a fiber optic assembly comprising at least one optical fiber;   extruding a first layer of a dielectric armor around the fiber optic assembly, wherein extruding the first layer comprises diverting a flow of a first extrusion material with a first profiling feature rotating in a first direction; and   extruding a second layer of a dielectric armor around the fiber optic assembly, wherein extruding the second layer comprises diverting a flow of an second extrusion material with a second profiling feature rotating in a second direction, wherein   wherein the first layer becomes bonded to the second layer.   
     
     
         12 . The method of  claim 11 , wherein diverting the flow of extrusion material using the first profiling feature includes relative rotational motion between the profiling feature and the fiber optic assembly, and wherein diverting the flow of extrusion material using the second profiling feature includes relative rotational motion between the profiling feature and the fiber optic assembly. 
     
     
         13 . The method of  claim 12 , wherein the first direction is opposite to the second direction.