Abstract

All-optical switching is attractive for the future ultrafast optical communications and computer systems. To fabricate compact ultrafast all-optical devices compatible for integration with laser diodes, one would like to find a semiconductor material with a large optical nonlinearity and a rapid recovery time. GaAs grown at low temperatures (GaAs:As) contains excess As that creates a high density of midgap states that can reduce the carrier lifetime down to less than 1 ps. This material also exhibits an enhanced carrier-induced index change as large as 0.1 for light resonant with the bandgap.² GaAsrAs appears to be well suited for fabrication of optical-switching devices that would be compact and ultrafast. However, the absorption in GaAs:As is larger than that seen for GaAs. It is important to understand and characterize this absorption process in order to maximize the figure of merit of this material for all-optical switching.³

© 1995 Optical Society of America