Optical fiber bundle and method of manufacture the same

Abstract

An optical fiber bundle that has better ultraviolet resistance characteristics at a wavelength range of 150 to 250 nm and that can be readily and cheaply manufactured with no risk of, for example, explosion during manufacturing and its manufacturing method are provided. In the optical fiber bundle, optical fibers including a core mainly containing silica glass and a cladding containing silica glass and fluorine are bundled and accommodated in a container. This container has optically transparent ends, accommodates hydrogen or deuterium as well as the optical fibers, and is sealed. The capacity of the container is 10 times or less as large as the volume of glass of the optical fibers. The method of manufacturing the optical fiber bundle includes the steps of impregnating the optical fibers with hydrogen or deuterium by keeping the optical fibers in a hydrogen or deuterium atmosphere; bundling the optical fibers and accommodating the bundled optical fibers in the container before the hydrogen or deuterium desorbs from the optical fibers; and sealing the container so that hydrogen or deuterium that has desorbed from the optical fibers can be kept in the container.

1 - 6 . (canceled) 
   
   
       7 . A method of manufacturing an optical fiber bundle, comprising the steps of:
 drawing optical fibers from a glass preform, each including a core mainly consisting of silica glass and a cladding consisting of silica glass and fluorine and having a lower refractive index than the core;   impregnating the optical fibers with hydrogen or deuterium by keeping the optical fibers in a hydrogen or deuterium atmosphere;   bundling the optical fibers and putting the bundled optical fibers in a container before the hydrogen or deuterium desorbs from the optical fibers; and   sealing the container so that the hydrogen or deuterium that has desorbed from the optical fibers can be kept in the container.   
   
   
       8 . A method of manufacturing an optical fiber bundle according to  claim 7 , wherein each core contains an OH or OD group of 100 to 1500 ppm by weight and chlorine of less than 50 ppm by weight before the step of impregnation with hydrogen or deuterium. 
   
   
       9 . A method of manufacturing an optical fiber bundle according to  claim 7 , wherein each core contains fluorine of 0.1% to 2.0% by weight and chlorine of less than 50 ppm by weight before the step of impregnation with hydrogen or deuterium. 
   
   
       10 . A method of manufacturing an optical fiber bundle according to  claim 7 , wherein the optical fibers have a loss of less than 4 dB/m at a wavelength of 245 nm before the step of impregnation with hydrogen or deuterium. 
   
   
       11 . A method of manufacturing an optical fiber bundle according to  claim 7 , wherein the optical fibers are impregnated with hydrogen or deuterium after the optical fibers are bundled. 
   
   
       12 . A method of manufacturing an optical fiber bundle according to  claim 7 , wherein the optical fibers contain hydrogen or deuterium of 5□1018 molecule/cm 3  or more after the step of impregnation with hydrogen or deuterium. 
   
   
       13 . A method of manufacturing an optical fiber bundle according to  claim 7 , wherein the volume of glass of the optical fibers, the content of hydrogen or deuterium in the optical fibers, and the capacity of the container are determined so that the partial pressure of hydrogen or deuterium in the container becomes 0.03 atm or more after the step of sealing the container.