| 摘要 |
PURPOSE:To secure a stable polarization preservability for a long distance against disturbance and to facilitate the connection of optical lines, by twisting the optical line around the axis of the core. CONSTITUTION:When the difference in specific refractive index between a core part 1 and a clad part 2, the used wavelength, and the refractive index of the core part 1 corresponding to the used wavelength are denoted as DELTA=(n1-n2)/ n1, lambda(mum), and n1(lambda) respectively, the unit length of the optical line is twisted in the same direction (indicated by an arrow 3) in the proportion of phit0=2.8X10<5> (n1(lambda)DELTA<2>/lambda)[radian/m]or more. Concretely, a line 4, which is parallel with the axis (axis Z), and is indicated by a one-dot broken line, on the outside circumferential face of the optical line is changed to a spiral line 5 indicated by solid lines and broken lines by twisting the optical line. In respect to a pitch Pt of twisting, Pt=2pi/phit is true. Thus, the preservability of linear polarization components is improved, and the preservability of circular polarization components is realized. |
