Thermally-shaped optical fiber and a method for forming the optical fiber

Abstract

A thermally-shaped optical fiber and a method for forming the same so as to minimize the presence of optical artifacts in the optical fiber that contributes to insertion loss.

1 . A method for forming an optical waveguide from an optical fiber having a longitudinal axis, said method comprising: 
 exposing a first region of said optical fiber to thermal energy, with a portion of said thermal energy being transferred to said optical fiber, defining transferred energy;    dissipating said transferred energy at a second region of said optical fiber, with said first and second regions being spaced-apart, with thermal energy passing between said first and second spaced-apart regions forming a flow; and    maintaining, in said flow, a constant rate of thermal transfer between said first and second spaced-apart regions, thereby providing a graded index of refraction in a portion of said optical fiber located between said first and second spaced-apart regions.    
   
   
       2 . The method as recited in  claim 1  wherein dissipating further includes removing said transferred energy from said optical fiber in a direction that extends radially with respect to said longitudinal axis.  
   
   
       3 . The method as recited in  claim 1  wherein dissipating further includes transferring said transferred energy away from said optical fiber radially symmetrically about said longitudinal axis.  
   
   
       4 . The method as recited in  claim 1  wherein said index of refraction changes approximately 4% between said first and second spaced-apart regions.  
   
   
       5 . The method as recited in  claim 1  wherein maintaining further includes avoiding variances in said thermal energy being transferred to said optical fiber proximate to said first region and avoiding variances in a rate of dissipation of said transferred thermal energy.  
   
   
       6 . The method as recited in  claim 1  further including segmenting said optical fiber proximate to said first region.  
   
   
       7 . The method as recited in  claim 6  wherein segmenting said optical fiber further includes forming a lens proximate to said first region, with said portion extending from said second region, toward said first region, terminating in a lens.  
   
   
       8 . The method as recited in  claim 1  wherein exposing said optical fiber further includes impinging a beam of infrared energy upon said optical fiber from a first direction and reflecting a subportion of said infrared energy to impinge upon said optical fiber from a second direction, with said second direction disposed opposite to said first direction.  
   
   
       9 . The method as recited in  claim 8  wherein a said subportion has a magnitude associated therewith, which is dependent upon a mode associated with said optical fiber.  
   
   
       10 . A method for controlling optical properties of an optical fiber having a longitudinal axis, said method comprising: 
 creating a flow of thermal energy between two spaced-apart regions of said optical fiber, with a flux of said thermal energy in said flow being substantially constant to define a graded index of refraction in a portion of said optical fiber located between said two-spaced apart regions.    
   
   
       11 . The method as recited in  claim 10  wherein said creating further includes exposing said first region of said optical fiber to said thermal energy, with a portion of said thermal energy being transferred to said optical fiber, defining transferred energy and dissipating said transferred energy at a second region of said optical fiber.  
   
   
       12 . The method as recited in  claim 11  wherein dissipating further includes transferring said transferred energy radially symmetrically away from said optical fiber.  
   
   
       13 . The method as recited in  claim 12  wherein exposing said optical fiber further includes impinging a beam of infrared energy upon said optical fiber from a first direction and reflecting a subportion of said infrared energy to impinge upon said optical fiber from a second direction, with said second direction disposed opposite to said first direction.  
   
   
       14 . The method as recited in  claim 13  wherein said subportion has a magnitude associated therewith, which is dependent upon a mode associated with said optical fiber.  
   
   
       15 . The method as recited in  claim 1  further including segmenting said optical fiber proximate to said first region to form a lens, with said portion extending from said second region, toward said first region, terminating in said lens.  
   
   
       16 . An optical waveguide, comprising: 
 an optical fiber having an interface region and an end region; and    a lens integrally formed to said interace region, with said interface region being disposed between said end region and said lens, said end region and said lens each having a constant index of refraction and said interface region defining a graded index of refraction.    
   
   
       17 . The optical waveguide as recited in  claim 16  wherein said graded index of refraction has a maximum value at said lens and a minimum value at said end region.  
   
   
       18 . The optical waveguide as recited in  claim 17  wherein said graded index of refraction has a median value, with said maximum value being approximately 2% greater than said median value and said minimum value being approximately 2% less than said median value.  
   
   
       19 . The optical waveguide as recited in  claim 16  wherein said lens is a convex lens.