| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical amplification fiber module consisting of an optically amplifying fiber and an optical input/output fiber, having a high efficiency of optical coupling of the fibers and simple to assemble. SOLUTION: The optically amplifying fiber 1 and the optical input/output fiber 2 of mutually different field modes are optically coupled with a rod lens whose refractive index varies in the radial direction with respect to the optical axis (GRIN rod lens 3). These have especially the same outside diameters and are aligned for their respective optical axes on the basis of the diameters. The optically amplifying fiber and the GRIN rod lens are coupled with an adhesive and the reflectance of the optically amplifying fiber is controlled by the refractive indexes and the thicknesses of adhesive layers 4a and 4b. |
