| 摘要 |
An in-line optical amplifier includes a pumping source, a rare-earth element doped fiber amplifier, a gain regulator and a noise detector. An input power and an output power of the in-line optical amplifier are detected from the input optical signal and the output optical signal, respectively, and then they are used to detect a resultant gain of the in-line optical amplifier. The gain regulator controls the pumping light emitted by a pumping source such that the gain of the rare-earth element doped fiber amplifier is increased and a gain deviation of the resultant gain from a predetermined gain is reduced. The noise detector detects an internal noise or a noise figure based on the gain deviation, for example, by detecting the intensity of the pumping light or the magnitude of drive current of the pumping source. |
