SINGLE-MODE OPTICAL FIBER OF CIRCULAR POLARIZATION MAINTAINABILITY AND ITS MANUFACTURE

摘要

PURPOSE:To obtain a long-sized optical fiber with small loss by providing a linear glass layer of glass composition which is slightly different in refractive index from core glass or clad glass near a core lengthwise in the core glass or clad glass. CONSTITUTION:The linear glass layer 2 of glass composition which is slightly different in refractive index from the core glass of a core part 1 or the clad glass of a clad layer 2 near the core part 1 is provided in the core glass or clad glass. Said linear glass layer 2 is formed linearly in the clad layer 3 contacting the core 1 while turned once per 1cm length of the fiber. The difference in refractive index between the core glass and linear glass layer is 0.1%. When laser light of clockwise circular polarization is made incident to this single-mode optical fiber of circular polarization maintainability, the combination with a counterclockwise circular polarized wave due to a dispersion of pulses is extremly small and the state of clockwise circular polarization is maintained very excellently. Consequently, the manufacture is simplified and the long-sized, small- loss fiber is formed.