| 摘要 |
PURPOSE:To prevent an oscillation due to a return light out of an apparatus in a wide temperature range by increasing a temperature range of a low Q value as compared with that of prior art in an optical amplifier for directly amplifying a signal light by introducing the light together with an exciting light to an amplifying optical fiber. CONSTITUTION:The optical amplifier comprises a first optical isolator 41, an amplifying optical fiber 1, an exciting light source 2, an optical mixer 3 for mixing a signal light to be incident to the fiber 1 and an exciting light to be incident from the source 2, and a second optical isolator 42. The amplifier has substantially a peak in the isolation of the isolator 41 at a desired temperature and substantially a peak in the isolation of the isolator 42 at a higher temperature by a suitable amount than the desired temperature. |
