Ultrafast Semiconductor carrier Dynamics Probed by Four-Wave Mixing and Application to All-Optical Signal Processing in WDM Systems

摘要

Four-wave mixing (FWM) in semiconductor optical amplifiers provides a frequency domain tool for probing a wide ragne of carrier relaxation phenomena. In the simplest configurations, two single frequency waves are introduced into the gain region of an optical amplifier, and then mix by way of several different mechanisms. Gain and refractive index modulation result from the mixing which subsequently scatters energy from the original waves to create new waves. In the small signal regime, two new waves are generated as illustrated in figure 1. These new waves are easily shown to have a phase conjugate relationship to one of the original input waves as illustrated in the figure.