| 摘要 |
PROBLEM TO BE SOLVED: To provide a polarization maintaining optical fiber having high and stable ability of maintaining a polarized state. SOLUTION: The polarization maintaining optical fiber 20 is composed of a core 11, a clad 12 surrounding the core 11, two of first stress imparting parts 13, 13 having a circular cross section and arranged almost symmetric around the core 11, and two of second stress imparting parts 14, 14 having a circular cross section and arranged almost symmetric around the core 11 in such a manner that the centers of the parts 14, 14 are on the straight line b-b which is perpendicular to the straight line a-a passing the centers of the parts 13, 13. The second stress imparting parts 14, 14 are made of quartz glass with addition of titania, quartz glass with addition of fluorine or a mixture glass of these. |
