| 摘要 |
PURPOSE:To reduce loss between concave lenses and convex lenses and to condense two wavelengths to the same point by adhering both of the lenses or one of them with a cylindrical refractive index distribution type lens to combine these lenses. CONSTITUTION:The optical axis of rod lenses coincides with that of concave lenses L3, L4 and is indicated by O-O' and the concave lenses are formed by an optical material having dispersion smaller than that of the rod lenses. The concave lenses L3, L4 closely contact with the rod lenses L1, L2 respectively and a composite focal distance obtained by combining the concave lenses and rod lenses is the same at two wavelength. If the end surface of an optical fiber F1 is put on the composite focal distance formed by the concave lenses and the rod lenses when it is defined that the light flux obtained by projecting light including two wavelength from the optical fiber F1 is R1, the light rays with respective wavelength are made parallel light flux R8, R9 having different diameters respectively by the concave lenses and the rod lenses, condensed by the rod lens L2 and the concave lens L4 and the combined light flux R10 is made incident to an optical fiber F2. |
