Optischer Verstärker

摘要

An optical amplifier using an optical fibre doped with a rare-earth element. The doped optical fibre amplifies an optical signal when pumped with light. The gain of the optical amplifier is controlled by using a signal obtained from a detector which detects the light emitted sideways from the optical fibre. The signal obtained from the detector is applied to a feedback network for controlling a light source which serves as a light pump. The control is in such a sense as to maintain the level of the sideways-emitted light substantially constant. An alternative optical amplifier uses a laser diode which amplifies an optical signal when pumped with current. Sideways-emitted light from the laser diode is used in the feedback network in this arrangement.