Methods and apparatus related to a distal end portion of an optical fiber having a substantially spherical shape

Abstract

An apparatus includes an optical fiber extending from a proximal end to a distal end. The optical fiber may include a cladding layer circumferentially disposed about a core layer and a substantially spherically shaped portion at the distal end. The apparatus may also include a first coating circumferentially disposed on a first length of the cladding layer, and a second coating circumferentially disposed on a second length of the cladding layer. The second length may extend distally from a region proximate the distal end of the first coating.

1 . An apparatus comprising:
 an optical fiber extending from a proximal end to a distal end, the optical fiber including a cladding layer circumferentially disposed about a core layer, the optical fiber further including a substantially spherically shaped portion at the distal end;   a first coating circumferentially disposed on a first length of the cladding layer; and   a second coating circumferentially disposed on a second length of the cladding layer, wherein the second length extends distally from a region proximate the distal end of the first coating.   
     
     
         2 . The apparatus of  claim 1 , wherein the second length extends from the distal end of the first length to a proximal end of the substantially spherically shaped portion. 
     
     
         3 . The apparatus of  claim 1 , wherein the second length extends from a region proximal to the distal end of the first length to a region distal to a proximal end of the substantially spherically shaped portion. 
     
     
         4 . The apparatus of  claim 1 , wherein a distal end of the second length is proximal to a distal end of the substantially spherically shaped portion. 
     
     
         5 . The apparatus of  claim 1 , wherein an index of refraction of the first coating is substantially equal to an index of refraction of the second coating. 
     
     
         6 . The apparatus of  claim 1 , wherein an index of refraction of the first coating is different from the index of refraction of the second coating. 
     
     
         7 . The apparatus of  claim 1 , wherein the first coating includes a first inner coating and a first outer coating, wherein the first inner coating is positioned radially inwards of the first outer coating. 
     
     
         8 . The apparatus of  claim 1 , wherein the second coating includes a second inner coating and a second outer coating, wherein the second inner coating is positioned radially inwards of the second outer coating. 
     
     
         9 . The apparatus of  claim 1 , wherein a diameter of the substantially spherically shaped portion is greater than a diameter of the cladding layer. 
     
     
         10 . The apparatus of  claim 1 , further including a recessed portion positioned between a distal end of the second length and a proximal end of the substantially spherically shaped portion, the recessed portion having an outer diameter smaller than an outer diameter of each of a portion distal to the recessed portion and a portion proximal to the recessed portion. 
     
     
         11 . A method of fabricating a medical device, comprising:
 removing a portion of a first coating at a distal end portion of an optical fiber such that an exposed portion of the optical fiber is exposed;   heating at least a first portion of the exposed portion to transform the first portion to a substantially spherically shaped portion of the exposed portion; and   disposing a second coating on at least a second portion of the exposed portion after the heating.   
     
     
         12 . The method of  claim 11 , wherein disposing the second coating includes disposing the second coating between a distal end of the first coating and a proximal end of the substantially spherically shaped portion. 
     
     
         13 . The method of  claim 11 , wherein disposing the second coating includes applying the second coating such that the substantially spherically shaped portion and a distal region of the first coating are coated. 
     
     
         14 . The method of  claim 11 , wherein the heating includes melting the first portion and allowing surface tension to transform the molten first portion to the substantially spherically shaped portion. 
     
     
         15 . The method of  claim 11 , further including applying a laser through the optical fiber to remove a portion of the second coating at a distal end of the substantially spherically shaped portion. 
     
     
         16 . A fiber optic medical device, comprising:
 a core extending from a proximal end to a distal end;   a cladding layer circumferentially disposed about the core and extending from the proximal end to the distal end;   a covering layer circumferentially disposed about the cladding layer and extending from the proximal end to a first end proximal to the distal end;   a substantially spherical optical component integral with the core and the, cladding layer positioned at the distal end; and   a coating circumferentially disposed about a region extending from proximate the first end towards the optical component.   
     
     
         17 . The device of  claim 16 , wherein a proximal end of the coating overlaps a distal end of the covering, and a distal end of the coating is positioned between a proximal end and a distal end of the optical component. 
     
     
         18 . The device of  claim 16 , wherein the coating includes an inner coating and an outer coating positioned radially outwards of the inner coating. 
     
     
         19 . The device of  claim 16 , wherein a diameter of the substantially spherical optical component is greater than a diameter of the cladding layer.