| 摘要 |
PROBLEM TO BE SOLVED: To enable signal light and exciting light to be efficiently coupled to and amplifying optical fiber through a simple structure in an optical fiber amplifying device with a double clad amplifying optical fiber. SOLUTION: A bundle fiber which comprises a signal light optical fiber 2 and an exciting light optical fiber 3-1 which propagates exciting light and is arranged adjacent to and parallel with the signal light fiber 2 is used. The signal light optical fiber 2 of the bundle fiber and the core of an amplifying optical fiber are optically coupled together, and the exciting light optical fibers 3-1 are arranged in the first clad of the amplifying optical fiber confronting the core of the amplifying optical fiber. At this point, the bundle fiber and the amplifying optical fiber are joined together through a butt joint method (two edge faces are butted together), or the bundle fiber and the amplifying optical fiber are optically coupled together through a refractive index-distributed lens provided between the bundle fiber and the amplifying optical fiber. The signal light optical fiber and the exciting light optical fiber are housed in a fiber ferrule 1, and a gap is filled up with a filler. The bundle fiber may be provided at either the input side or output side of the amplifying optical fiber. |
