| 摘要 |
PURPOSE:To obtain the rare earth element-doped optical fiber having the highest amplification degree of signal light in the same excitation light input. CONSTITUTION:The signal light entering from a signal light input terminal 2 is passed through a multiplexer 5 and is made incident on the rare earth element-doped optical fiber 1g formed by periodically fusion splicing four kinds of rare earth element-doped optical fiber 1c to rare earth element-doped optical fiber 1f varying in the radii of the regions doped with rare earth elements and by approximating the average doping concn. distribution per length 4L to a Gaussion distribution. The excitation light emitted from an excitation light source 4 is passed through the multiplexer 5 and is then made incident on the rare earth element-doped optical fiber 1g, by which the signal light is amplified. The amplified signal light is emitted from the rare earth element- doped optical fiber 1g. The average doping concn. distribution of the rare earth element-doped optical fiber 1g is approximate to the intensity distribution of the excitation light and, therefore, the excitation light is efficiently absorbed and the rare earth element-doped optical fiber having the high excitation efficiency is obtd. |
