Abstract

Semiconductor optical amplifiers will be important components for high-repetition rate optical systems, such as optical time division multiplexed systems [1]. Several groups have studied the properties of optical amplifiers when used with ultrashort input optical pulses [2-4]. If the input pulse is sufficiently energetic, it can compress (saturate) the gain of the amplifier by removal of a fraction of carriers from the active region by stimulated emission [2,4]. After passage of the input pulse, the amplifier gain will recover with a time constant, τ. When the separation between input pulses becomes comparable to or smaller than τ, the gain experienced by a particular pulse will depend on the previous pulse pattern incident on the amplifier, because the gain may not have time to recover to its original value between pulses. Thus, it is important to understand the effect of gain recovery on the gain experienced by a randomly modulated pulse stream, because the finite gain recovery time may lead to inter-symbol interference (ISI). To gain insight into this problem, we study gain compression of an InGaAsP optical amplifier when used with multi-gigahertz repetition rate pulse streams.

© 1989 Optical Society of America