| 摘要 |
PROBLEM TO BE SOLVED: To improve the energy conversion efficiency of an optical amplifier and, at the same time, to reduce the waveform dependency of the gain of the amplifier. SOLUTION: In two-stage EDFs 2a and 2b connected to a light circulator 1, the first-stage EDF 2a is set at 0.98μm excitation and the second-stage EDF 2b is set at 1.48μm excitation. Therefore, the energy conversion efficiency of an optical amplifier can be further improved than that constituted in such a way that the optical amplifier in which both the EDFs 2a and 2b are set at 0.98μm excitation. In addition, a low-noise characteristic can be maintained, because the first-stage EDF 2a is set at 0.98μm excitation. |
