A FEED FORWARD METHOD FOR STABILIZING THE GAIN AND OUTPUT POWER OF AN ERBIUM-DOPED FIBER AMPLIFIER

摘要

The gain and the output power of an erbium-doped fiber amplifier (EDFA) are found to be sensitive to input power level fluctuations. Many feed back methods have been proposed to stabilize the gain of an EDFA. These feed back methods are based on sampling and detecting output light and using it to control the pump laser. Such methods fail when the amplifier is expected to repeat a multi-gigabit data stream. It then becomes necessary to use all more complex optical feed back methods to stabilize the gain. In this article, we propose a novel feed forward technique for stabilizing the output power or gain of an EDFA. A lithium niobate (LiNbO{sub}3)-based Mach-Zehnder interferometer is used to modulate the intensity of pump light in accordance with the input signal level so as to retain constant output power or gain. We observe that the gain or output power of EDFA can be stabilized by proper selection of the parameters of EDFA and modulator.