Gain stabilized fiber amplifier.

摘要

In this invention an optical fiber doped with a rare earth element and coupled to be pumped with a laser is coupled to an optical feedback loop. The feedback loop couples the output signal of the fiber amplifier to the input of the fiber amplifier. A narrow bandwidth filter coupled to the feedback loop allows a selected wavelength of the amplified spontaneous emission to pass from the output of the fiber amplifier to the input of the fiber amplifier. The feedback signal has a wavelength which is different from that of the pump signal and the wavelengths of the signals to be amplified. in operation, when bursts of optical signals from at least two discrete word or frequency division multiplexed channels are amplified in the fiber amplifier, the undesired fluctuations of gain of the output signals normally due to transient saturabon of the erbium-doped filter amplifier are substantially eliminated. <IMAGE>