Tip reflection reduction for shape-sensing optical fiber

Abstract

A method for end-reflection reduction of an optical shape-sensing fiber is described. The includes: providing a tip portion having a length dimension (d); connecting the tip portion to an end portion of an optical fiber configured for optical shape-sensing, the tip portion being indexed matched to the optical fiber; and adjusting the absorption properties of the tip portion using back reflections as feedback to provide an absorption length for light traveling in the optical fiber to reduce the back reflections.

1 . A method for reducing end-reflection of an optical shape-sensing fiber, the method comprising:
 providing a tip portion having a length dimension;   connecting the tip portion to an end portion of an optical fiber configured for optical shape-sensing, the tip portion being indexed matched to the optical fiber; and   adjusting the absorption properties of the tip portion using back reflections as feedback to provide an absorption length for light traveling in the optical fiber to reduce the back reflections.   
     
     
         2 . The method as recited in  claim 1 , the tip portion comprising an absorption length having at least one material on interior and exterior portions of the absorption length that is configured to absorb and scatter light within the length dimension, wherein the absorption length for light traveling in the optical fiber is less than the length dimension. 
     
     
         3 . The method as recited in  claim 1 , wherein the tip portion comprises a length dimension that is less than about 5 mm. 
     
     
         4 . The method as recited in  claim 1 , wherein the tip portion comprises a media having light absorbing dopants or particulates and the step of adjusting the absorption properties comprises adjusting a concentration of dopants or particulates. 
     
     
         5 . The method as recited in  claim 4 , wherein the light absorbing dopants or particulates comprise one or more of graphite, nanotubes, buckyballs, a metal complex or particles, cations, anions, a modified metal material fabricated by femtosecond etching lasers for surface modification of a metallic substrate and a dye. 
     
     
         6 . The method as recited in  claim 4 , wherein the light absorbing dopants or particulates comprise a metal having a relative permittivity of about 2 at a plasmon frequency. 
     
     
         7 . The method as recited in  claim 4 , wherein the light absorbing dopants or particulates have a minimum reflection extinction coefficient (k min ) for a given length dimension of the tip portion. 
     
     
         8 . The method as recited in  claim 4 , wherein the tip portion comprises a material with an index of refraction matched to that of the optical fiber and a minimum reflection extinction coefficient (k min ) for a given length dimension of the tip portion. 
     
     
         9 . The method as recited in  claim 1 , further comprising providing the tip portion with a distal end surface comprising a light dispersive shape or finish. 
     
     
         10 . A method for reducing end-reflection of an optical shape-sensing fiber, the method comprising:
 providing a shape sensing enabled medical device having at least one optical fiber;   providing a console configured to receive optical signals from the at least one optical fiber and interpret the optical signals to determine a shape of the medical device; and   providing a tip portion coupled to a distal end portion of the at least one optical fiber, the tip portion comprising: an absorption length having at least one material on interior and exterior portions of the absorption length that is configured to absorb and scatter light within the length dimension; and a surface opposite the end portion having a shape comprising ridges or a slant that is configured to reduce back reflections.   
     
     
         11 . The method of  claim 10 , wherein the tip portion comprises a media having light absorbing dopants or particulates. 
     
     
         12 . The system as recited in  claim 10 , wherein the light absorbing dopants or particulates comprise a metal having a relative permittivity of about 2 at a plasmon frequency. 
     
     
         13 . The method as recited in  claim 10 , wherein the light absorbing dopants or particulates have a minimum reflection extinction coefficient (kmin) for a given length dimension. 
     
     
         14 . The method as recited in  claim 10 , wherein the tip portion comprises a material with an index of refraction matched to that of the optical fiber and a minimum reflection extinction coefficient (kmin) for a given length dimension.