Optical fiber assemblies, and methods and apparatus for the manufacture thereof

Abstract

Methods for manufacturing cables and cables assemblies include providing powder particles within a tube extruded about optical fiber. The particles may be accelerated so that as they strike the tube and mechanically attach to the tube.

1 . (canceled) 
     
     
         2 . A method, comprising:
 extruding a tube about an optical fiber, wherein during the extruding an extrusion cone is formed about the optical fiber; and   applying a particulate material to an interior of the extrusion cone such that at least a portion of the particulate material is mechanically attached to the extrusion cone.   
     
     
         3 . The method of  claim 2 , wherein the particulate material comprises a water swellable powder. 
     
     
         4 . The method of  claim 2 , wherein the particulate material comprises flame-retardant particles. 
     
     
         5 . The method of  claim 2 , wherein the particulate material comprises a dry lubricant material. 
     
     
         6 . The method of  claim 5 , wherein the dry lubricant material comprises at least one of talc, graphite, or boron. 
     
     
         7 . The method of  claim 2 , wherein the extrusion cone shrinks radially to form a tube after the particulate material is applied to the interior of the extrusion cone. 
     
     
         8 . The method of  claim 2 , further comprising:
 mixing the particulate material with a motive gas to form a particulate/gas mixture, wherein applying the particulate material to the interior of the extrusion cone comprises conveying the particulate/gas mixture toward the interior of the extrusion cone.   
     
     
         9 . The method of  claim 8 , wherein mixing the particulate material with the motive gas comprises:
 conveying the motive gas past an aperture formed in a funnel, the funnel containing a supply of the particulate material, wherein a portion of the supply of the particulate material is drawn through the aperture and into a mixing chamber responsive to the motive gas being conveyed past the aperture.   
     
     
         10 . The method of  claim 8 , wherein the particulate/gas mixture is conveyed toward the interior of the extrusion cone at a velocity of greater than or equal to 5 meters per second. 
     
     
         11 . The method of  claim 8 , wherein the particulate/gas mixture is conveyed toward the interior of the extrusion cone at a velocity of greater than or equal to 20 meters per second. 
     
     
         12 . The method of  claim 2 , wherein a temperature of the extrusion cone is at least 160° C. 
     
     
         13 . The method of  claim 2 , wherein the portion of the particulate matter that mechanically attaches to the extrusion cone is up to 60% by weight of the particulate matter. 
     
     
         14 . The method of  claim 13 , further comprising:
 exhausting, out of the tube, a second portion of the particulate matter that does not mechanically attach to the extrusion cone.   
     
     
         15 . The method of  claim 14 , wherein the second portion is 10-25% by weight of the particulate matter. 
     
     
         16 . A method, comprising:
 providing an optical fiber;   forming a tube about the optical fiber; and   conveying a mixture of motive gas and particulate matter to an interior of the tube while the tube is in a partially molten state and with sufficient velocity so that at least a portion of the particulate matter deforms an interior surface of the tube and becomes mechanically attached to the tube.   
     
     
         17 . The method of  claim 16 , wherein conveying the mixture to the interior of the tube comprises:
 conveying the mixture through an annular passage disposed between an inner sleeve and an outer sleeve, wherein the optical fiber is disposed in an interior of the inner sleeve;   
       and 
       wherein forming the tube about the optical fiber comprises:
 extruding a polymeric material around the optical fiber to form the tube. 
 
     
     
         18 . The method of  claim 17 , wherein the polymeric material is extruded by way of an extrusion tip disposed concentrically about the outer sleeve. 
     
     
         19 . The method of  claim 17 , further comprises conveying the motive gas and a second portion of the particulate matter away from the tube and in a second direction opposite to a first direction through which the mixture is conveyed through the annular passage, the second portion of the particulate matter being that portion of the particulate matter that does not become mechanically attached to the tube. 
     
     
         20 . The method of  claim 16 , wherein subsequent to forming the tube and conveying the mixture to the interior of the tube, a normalized concentration of the particulate matter in the tube is less than about 0.01 grams of the particulate matter per meter length of the tube per square millimeter of a cross-sectional area of the interior of the tube after drawdown of the tube. 
     
     
         21 . A system comprising:
 an extrusion apparatus that receives an optical fiber and extrudes a jacket about the optical fiber; and   a powder application apparatus that applies a powder to an interior of an extrusion cone formed by the extrusion apparatus during extrusion of the jacket, the interior of the extrusion cone being an interior surface of the jacket, wherein the powder application apparatus applies the powder to the interior of the extrusion cone such that a portion of the powder is mechanically attached to the extrusion cone.