| 摘要 |
PURPOSE:To obtain an optical branching device of a low loss, which is applicable to a loop-like transmission line without a problem, by constituting so that an end face of 2 optical fibers is cut at a prescribed angle against the center axis, and a half-mirror is directly formed on one end face and is junctioned with the other end face. CONSTITUTION:As for optical fibers 51, 52, its end face is cut at an angle of about 45 deg. against the ceter axis, and is polished. Subsequently, on the end face of the optical fiber 51, a half-mirror 53 consisting of a metallic film and a dielectric layer and having optional reflection and transmission characteristics is formed, and the end face of the other optical fibers 52 is butted to this half- mirror 53 so that the optical axes coincide and is stuck by an adhesive. An insertion loss to the optical fiber 52 from the optical fiber 51 becomes the same extent as that which has connected a regular optical fiber, except a loss of a portion which has been made to branch by reflection of the half-mirror 53, and when this optical branching device is applied to a loop-like optical transmission line, a stable system of a low loss can be constituted. |
