| 摘要 |
PURPOSE: To provide a prism interference method using a prism having no reflection surface. CONSTITUTION: An optical fiber 1 has a core to which Ge is added, and a laser beam 6 is an ultraviolte ray whose wavelength is near 240nm. The laser beam 6 made incident on one incident surface 4 and the other incident surface 5 interposing the apex 3 of a triangle pole prism 2 is refracted on each surface, passes through the prism 2, and irradiates the core part of the optical fiber 1 with interference fringe at an equal interval. At a part where the interference fringe is bright, refractive index rises, and at the core part of the optical fiber 1, the refractive index is changed in the pattern in accordance with the interference fringe, so that the diffraction grating is formed. |
