| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical amplifier using an optical fiber in which the exciting light power in the optical amplifier can be controlled in the longitudinal direction of the optical fiber with no attenuation, while fixing the supply position of the exciting light to one position.SOLUTION: In an optical amplifier where a core 13 added with a rare earth element is an amplification medium of an optical signal, and the exciting light for bringing the rare earth element into an excited state is supplied via a clad 11 on the outside of the core 13, coupling means for (inverse coupling long period fiber grating structure 20) for coupling the exciting light, supplied to the clad 11 and propagating in the clad 11 in a clad mode, with the core mode of the core 13 is provided, and the exciting light power is controlled in the longitudinal direction, by providing a plurality of the coupling means while distributing in the longitudinal direction of the optical amplifier.SELECTED DRAWING: Figure 6 |
