| 摘要 |
PURPOSE:To obtain an optical branching and inserting device which has less loss and causes no return light, by using a polarizing beam splitter, a Faraday effect element, and an optical rotation element. CONSTITUTION:In the figure, incident light from an optical fiber 11a is split by a polarizing beam splitter Ba; S-polarized light is reflected by the composition surface of a polarizing beam splitter 13d and coupled with an optical fiber 13b to propagate through it, and P-polarized light has its plane of polarization rotated at 45 deg. by a Faraday effect element 14 and at -45 deg. by an optical rotation element 16, and is then passed through a polarizing beam splitter 11b and reflected by a wedge-shaped reflecting mirror 17 to be coupled with a photodetecting element 18. On the other hand, laser beam from a light emitting element 19 is reflected by the composition surface of polarizing beam splitters 13b and 13c, has the plane of polarization rotated at 90 deg. by the Faraday effect element 14, and is coupled with optical fibers 11a and 11b through polarizing beam splitters 13a and 13d. |
