Optical fiber having reduced defect density

Abstract

An optical fiber comprising a multimode glass core having a diameter of at least 250 microns and an index of refraction and a polymer cladding having a thickness and contactingly surrounding a glass portion of the fiber so as to define an interface between the glass portion and the polymer cladding. The polymer cladding can have a first index of refraction that is less than the index of refraction. The fiber can comprise a density of less than 0.25 non-conforming regions having a diameter of 25 microns or greater per millimeter of length along the fiber, where each of the non-conforming regions is a region visible to the human eye under an optical microscope and having at least a portion thereof within a selected distance of the interface. The selected distance can be less than or equal to the thickness of the polymer cladding. The optical microscope can have a total magnification of about 200. The polymer cladding can be applied to at least a part of the optical fiber in at least a class 1000 environment. Methods of using optical fibers, including receiving with an optical fiber optical energy from a source and guiding the optical energy with the optical fiber, wherein the optical energy comprises at least one of 1) pulses each comprising a peak power of at least 10 kW, 2) an average power of at least 50 Watts, or 3) an average power density of at least 2.9 kW/cm 2 .

1 . An optical fiber for delivering optical energy including a selected wavelength to or from a work object, comprising:
 a multimode glass core comprising a diameter of at least 250 microns, said core comprising an index of refraction;   a polymer cladding contactingly surrounding a glass portion of said fiber, said polymer cladding comprising a first index of refraction that is less than said index of refraction; and   wherein said polymer cladding is applied to at least a part of said fiber in at least a class 1000 environment.   
   
   
       2 . The optical fiber of  claim 1  wherein said polymer cladding comprises a hard polymer. 
   
   
       3 . The optical fiber of  claim 1  wherein said core consists essentially of silica glass. 
   
   
       4 . The optical fiber of  claim 1  wherein said environment is at least a class 100 environment. 
   
   
       5 . The optical fiber of  claim 1  wherein said polymer cladding contactingly surrounds said core. 
   
   
       6 . A method of delivering light to or from a work object, comprising:
 providing a source of optical energy;   providing an optical fiber having a glass core, the process of making the fiber having included drawing the optical fiber from a preform and applying, in at least a class 1000 environment, a polymer cladding to a glass portion of the optical fiber, the core having an index of refraction and a diameter of at least 250 microns and the polymer cladding having a first index of refraction that is less than the index of refraction; and   receiving with the optical fiber optical energy from the source and guiding the optical energy with the optical fiber, wherein the optical energy comprises at least one of 1) pulses each comprising a peak power of at least 10 kW, 2) an average power of at least 50 Watts, or 3) an average power density of at least 2.9 kW/cm 2 .   
   
   
       7 . The method of  claim 6  wherein the optical energy comprises the pulses each having a peak power of at least 10 kW. 
   
   
       8 . The method of  claim 6  wherein the optical energy comprises the average power of at least 50 Watts. 
   
   
       9 . The method of  claim 6  wherein the optical energy comprises the average power density of at least 2.9 kW.