Sub-miniature optical fiber cables, and apparatuses and methods for making the sub-miniature optical fiber cables

Abstract

A simplex optical fiber cable of this invention includes an optical fiber, a buffer preferably of nylon, surrounding and in contact with the optical fiber, a yarn layer with strength fibers, preferably aramid fibers, disposed about the buffer and a sheath preferably formed of polyvinyl chloride (PVC) surrounding and in contact with the yarn layer. [In cross-section, the simplex optical fiber cable has a diameter less than 2.0 millimeters (mm), and thus is much smaller in diameter than optical fiber cables presently available Preferably, if the buffer is relatively thin providing limited protection to the optical fiber, a slick substance such as talc is applied to an outer surface of the buffer before the yarn layer is disposed thereon. The slick substance allows the buffer of the optical fiber to slide to a degree in contact with the yarn layer and thus reduces fatigue caused by axial movement of a ferrule of the connector terminating the optical fiber cable. On the other hand, if the buffer is relatively thick, a friction-reducing substance such as Modaflo™ can be applied to the optical fiber to allow the buffer to be stripped relatively easily]. A zip-cord duplex optical fiber cable of this invention includes essentially two simplex optical fiber cables with their respective sheaths joining at a middle portion along the axial length of the simplex optical fiber cables. [Thus, in cross-section, the zip-cord duplex optical fiber cable has a figure-eight shape with a relatively thin portion in the middle which can be manually pulled apart to separate the zip-cord duplex optical fiber cable into separate simplex optical fiber cables. This feature of the invention allows the zip-cord duplex optical fiber cable to be split at its ends to allow connectors attached to respective ends of the optical fiber cables for connection to respective spaced connector receptacles]. A second duplex optical fiber cable of this invention includes two simplex optical fiber cables arranged side-by-side with an oversheath extruded about and holding together the two simplex optical fiber cables. In cross-section, the two duplex optical fiber cables of this invention are less than 2.0 mm in height and 4.0 mm in width, and thus are much smaller than currently available duplex optical fiber cables. [The invention also includes die assemblies and methods for making the simplex and duplex optical fiber cables].

1 . An optical fiber cable, comprising: 
 a single optical waveguide fiber having an outer coating, said outer coating having a diameter of about 500 μm;    a layer of loose tensile fibers surrounding the optical waveguide fiber outer coating; and    a tubular jacket of plastic material having an outer diameter D 2  surrounding the layer of loose tensile fibers, D 2  not exceeding about 1500 μm, said cable containing no gel like compounds.    
     
     
         2 . An optical fiber cable qas set out in  claim 1  wherein D 2  does not exceed about 1400 μm.  
     
     
         3 . An optical fiber cable as set out in  claim 1  wherein D 2  does not exceed about 1200 μm.  
     
     
         4 . An optical fiber cable as set out in  claim 1  wherein the optical fiber cable outer jacket is formed of a flame retardant material.  
     
     
         5 . An optical fiber cable as set out in  claim 1  wherein the tubular jacket has an inner diameter D 1  and D 2 −D 1  is less than or equal to about 300 μm.  
     
     
         6 . An optical fiber cable as set out in  claim 1  which contains no material comprising halogen compounds.  
     
     
         7 . An optical fiber cable as claimed in  claim 1  which contains no materials containing leaded compounds.  
     
     
         8 . An optical fiber cable comprising first and second optical fibers; 
 a first buffer composed of plastic material surrounding and in contact with an outer surface of the first optical fiber;    a second buffer composed of plastic material surrounding and in contact with an outer surface of the second optical fiber;    each of said buffers being surrounded by a yarn layer composed of strength fibers;    a sheath member surrounding and in contact with the yarn layer;    said cable having at least one transverse dimension in the range of 1.25 mm. to 2.00 mm.    
     
     
         9 . An optical fiber cable as claimed in  claim 8  wherein said transverse dimension is less than 2 mm.  
     
     
         10 . An optical fiber cable, comprising: 
 a single optical waveguide fiber having an outer buffer, said outer buffer having an outer diameter from about 500 μm to about 900 μm;    a layer of loose tensile fibers surrounding the optical waveguide fiber outer buffer; and    a tubular jacket of plastic material surrounding the layer of loose tensile fibers, said tubular jacket having an outer diameter not exceeding about 2000 μm, said cable containing no gel-like compounds.    
     
     
         11 . The optical fiber cable of  claim 10 , wherein said outer buffer has an outer diameter of about 900 μm.  
     
     
         12 . The optical fiber cable of  claim 10 , wherein said tubular jacket of plastic material surrounding the layer of loose tensile fibers has an outer diameter not exceeding about 1600 μm.  
     
     
         13 . An optical fiber cable, comprising: 
 a single optical waveguide fiber having an outer buffer, said outer buffer having an outer diameter of about 900 μm;    a layer of loose tensile fibers surrounding the optical waveguide fiber outer buffer; and    a tubular jacket of plastic material surrounding the layer of loose tensile fibers, said tubular jacket having an outer diameter of about 1600 μm, said cable containing no gel-like compounds.    
     
     
         14 . An optical fiber cable comprising first and second optical fibers; 
 a first outer buffer composed of plastic material surrounding and in contact with an outer surface of said first optical fiber;    a second outer buffer composed of plastic material surrounding and in contact with an outer surface of said second optical fiber;    each of said outer buffers being surrounded by a yarn layer composed of strength fibers; and    a sheath member surrounding and in contact with said yarn layer;    said cable having at least one outer transverse dimension not exceeding about 2000 μm.    
     
     
         15 . The optical fiber cable of  claim 14 , wherein said outer transverse dimension does not exceed about 1600 μm.  
     
     
         16 . The optical fiber cable of  claim 14 , wherein said first and second outer buffers have outer diameters from about 500 μm to about 900 μm.  
     
     
         17 . The optical fiber cable of  claim 14 , wherein said first and second outer buffers have outer diameters of about 900 μm.  
     
     
         18 . An optical fiber cable comprising first and second optical fibers; 
 a first outer buffer composed of plastic material surrounding and in contact with an outer surface of said first optical fiber, said first outer buffer having an outer diameter of about 900 μm;    a second outer buffer composed of plastic material surrounding and in contact with an outer surface of said second optical fiber, said second outer buffer having an outer diameter of about 900 μm;    each of said outer buffers being surrounded by a yarn layer composed of strength fibers; and    a sheath member surrounding and in contact with said yarn layer;    said cable having at least one outer transverse dimension of about 1600 μm.    
     
     
         19 . An optical fiber cable, comprising: 
 a single optical waveguide fiber having an outer buffer, said outer buffer having an outer diameter from about 500 μm to about 900 μm;    a layer of loose tensile fibers surrounding said optical waveguide fiber outer buffer; and    a tubular jacket of plastic material surrounding said layer of loose tensile fibers, said tubular jacket having an outer diameter from about 1000 μm to about 1800 μm, said cable containing no gel-like compounds.    
     
     
         20 . The optical fiber cable of  claim 19 , wherein said outer buffer has an outer diameter of about 500 μm.  
     
     
         21 . The optical fiber cable of  claim 19 , wherein said outer buffer has an outer diameter of about 900 μm.  
     
     
         22 . The optical fiber cable of  claim 19 , wherein said tubular jacket of plastic material surrounding said layer of loose tensile fibers has an outer diameter not exceeding about 1600 μm.  
     
     
         23 . The optical fiber cable of  claim 19 , wherein said tubular jacket of plastic material surrounding said layer of loose tensile fibers has an outer diameter of about 1600 μm.  
     
     
         24 . An optical fiber cable, comprising: 
 a single optical waveguide fiber having an outer buffer, said outer buffer having an outer diameter from about 500 μm to about 900 μm;    a layer of loose tensile fibers surrounding said optical waveguide fiber outer buffer; and    a tubular jacket of plastic material surrounding said layer of loose tensile fibers, said tubular jacket having an outer diameter from about 1200 μm to about 1600 μm, said cable containing no gel-like compounds.    
     
     
         25 . The optical fiber cable of  claim 24 , wherein said outer buffer has an outer diameter of about 500 μm.  
     
     
         26 . The optical fiber cable of  claim 24 , wherein said outer buffer has an outer diameter of about 900 μm.  
     
     
         27 . An optical fiber cable, comprising: 
 a single optical waveguide fiber having an outer buffer, said outer buffer having an outer diameter of about 900 μm;    a layer of loose tensile fibers surrounding said optical waveguide fiber outer buffer; and    a tubular jacket of plastic material surrounding said layer of loose tensile fibers, said tubular jacket having an outer diameter of about 1600 μm, said cable containing no gel-like compounds.    
     
     
         28 . An optical fiber cable comprising first and second optical fibers; 
 a first outer buffer composed of plastic material surrounding and in contact with an outer surface of said first optical fiber;    a second outer buffer composed of plastic material surrounding and in contact with an outer surface of said second optical fiber;    each of said outer buffers being surrounded by a yarn layer composed of strength fibers; and    a sheath member surrounding and in contact with said yarn layer;    said cable having at least one outer transverse dimension from about 1250 μm to about 2000 μm.    
     
     
         29 . The optical fiber cable of  claim 28 , wherein said outer transverse dimension does not exceed about 1680 μm.  
     
     
         30 . The optical fiber cable of  claim 28 , wherein said outer transverse dimension is about 1600 μm.  
     
     
         31 . The optical fiber cable of  claim 28 , wherein said first and second outer buffers have outer diameters from about 500 μm to about 900 μm.  
     
     
         32 . The optical fiber cable of  claim 28 , wherein said first and second outer buffers have outer diameters of about 500 μm.  
     
     
         33 . The optical fiber cable of  claim 28 , wherein said first and second outer buffers have outer diameters of about 900 μm.