Abstract

Energy storage capacity in an optical amplifier determines the pulse energy that can be extracted from an amplifier system. In the fiber amplifier, the energy storage is limited by self-gain saturation. Typically, the power leak to amplified spontaneous emission (ASE) limits the stored energy. Since the pump builds up the stored energy between the pulses, the pulse repetition rate should be small enough to ensure a complete gain recovery between subsequent pulses. It is possible to suppress the ASE by using optical elements with non-linear transfer functions in such a way that any low power noise experiences a net loss, while a high power signal pulse experiences a net gain. The nonlinear characteristics of saturable absorption in semiconductors can be utilized for such ASE suppression [1-2].

© 2002 Optical Society of America