Abstract

Carrier heating (CH) and spectral hole burning (SHB) have been proposed as the processes underlying the ultrafast dynamics of active semiconductor devices. The heating of the carrier distributions by interaction with an electromagnetic held was first proposed by Ippen’s group.¹ The generation of a spectral hole in the carrier distribution by stimulated recombination has been proposed by other researchers. CH is both resistive and reactive, and it affects gain and refractive index; SHB, because of the symmetry of the hole burned in the frequency domain, is mainly resistive, thus producing gain compression without affecting the index. Pulsed pump-probe experiments have shown the dominant role of CH,¹ although recently SHB has also been observed.² Four-wave-mixing (FWM) experiments have confirmed that carrier heating is the dominant mechanism for the nonlinearity.³ A single experiment, however, showed evidence of ultrafast nonlinearity inconsistent with CH, Because of the fast response and its resistive nature, it was ascribed to SHB.⁴

© 1994 Optical Society of America