| 摘要 |
PURPOSE:To form a preform for a constant polarization optical fiber coupling line and facilitate the manufacture by employing vaporphase etching in a process of manufacture of a base material by an MCVD method. CONSTITUTION:An SiO2 layer is stuck as a barrier layer on the internal wall surface of a starting quartz pipe 1 by the MCVD method and then a clad layer 21 is provided. Further, a stress inducing layer 31 is provided on the internal wall surface and parts 32 where the layers is removed completely by vapor- phase etching are formed; and the stress inducing layer 31 is separated into two in a circumferential direction. A clad layer 22 is formed and a core layer 41 is formed on its internal wall surface. The quartz pipe 1 lined with the respective layers is collapsed and made solid to manufacture the preform, which is a spinning device into fibers, thus obtaining the constant polarization optical fiber coupling line. |
