| 摘要 |
PURPOSE:To make possible changing of the spot size of luminous fluxes and reduce the light losses at the connecting of optical fibers by setting the specified relations between the refractive index within the respective sections of two rod lenses and the spot size of parallel luminous fluxes. CONSTITUTION:Rod lenses 11 and 12 are held firmly coupled on the same optical axis on their bonding face 13. When the luminous fluxes 14 whose spot size is x are entered to the lens 11, the luminous fluxes are focused in the lens and concentrate at the portion 15 of the bonding face 13, where they are converted to the luminous flux of opening angle theta and this luminous flux is entered to the lens 12, by which it is converted to parallel luminous fluxes 16 whose spot size is x'. These parallel luminous fluxes are then emitted therefrom. If in this case the refractive index on the central axis of each lens, the degree of inclination of the refractive index in the radial direction and the effective diameter of the core are let to be n0, g, b in the lens 11 and n0', g', b' in the lens 12, then setting such as the having the relations of x'/x to n0g/n0'g', b x is accomplished. |
