| 摘要 |
PURPOSE:To prevent the deterioration of the characteristic of a multimode optical fiber transmission line by installing an optical beam conversion mechanism composed of a magnifying glass and a slit with a coaxial circular projection on a plane perpendicular to the optical axis of a magnifying glass system between a single mode optical fiber and a multimode optical fiber. CONSTITUTION:While an optical beam emitted from the tip of the single mode optical fiber held in an input terminal 12 is converged by a converging rod lens 15, it makes incident on the multimode optical fiber 14 held in an output terminal 13. The slit 16 is constructed with a metallic film which is held at the optical axis 21 in the converging rod lens 15 and tilts by the prescribed angle from the vertical plane, has the coaxial circular projection on the vertical plane of the optical axis of the rod lens 15, and removes the unnecessary light on the periphery, which is caused by the aberration of the rod lens 15, out of an optical path by means of reflection. Thus the deterioration of the transmission characteristic in the multimode optical fiber 14 can be effectively prevented. |
