POLARIZING PLANE MAINTAINING OPTICAL FIBER

摘要

PURPOSE:To improve a quenching ratio characteristic by dividing the refractive index distribution of an elliptical jacket in the circumferential direction thereof and constituting an optical fiber so as to have the refractive index lower than the reflective index of a clad in the major axis direction of the ellipse and the refractive index higher than a clad in the minor axis direction. CONSTITUTION:The clad 2 consisting of pure SiO2 glass is provided to the outside peripheral part of the core 1 consisting of the SiO2 glass added with Ge so as to enclose said part. The elliptical jacket 3 is provided to the outside peripheral part of the clad 2 so as to enclose the same. The elliptical jacket 3 consists of SiO2 glass added with P2O5 and B2O3 and has a large coefft. of expansion. The B2O3 is added at the higher ratio in the major X-axis direction thereof and the refractive index n1 lower than the refractive index n0 of the clad 2 is provided so that the cut off wavelength of the polarization mode in the major axis direction is longer. The P2O5 is added at the higher ratio in the minor Y-axis direction and the refractive index n2 higher than the refrac tive index n0 of the clad 2 is provided so that the cut off wavelength of the polarization mode in the minor axis direction is shorter. The quenching ratio is thus improved.