Analysis of subpicosecond full-switching with a symmetric Mach-Zehnder all-optical switch

We present subpicosecond full-switching with a symmetric Mach-Zehnder all-optical switch. To the best of our knowledge, this is the fastest all-optical switching experiment with incoherent and thus realistic, efficient optical nonlinearities. We discuss various factors which possibly limit the switching speed. Present switching speed is determined only by the rise time of interband carrier excitation. Our analysis suggests that by reducing the duration of the control pulse, raster switching in the range from 100 to 200 fs can be expected, in which control pulse broadening due to group velocity dispersion is the dominant limitation.