Coherent Ultrafast All-Optical Switching in Fibers

All-optical switching reported to date in fibers or channel waveguides has relied on having a high intensity beam to either switch itself between two waveguides, or to switch a low intensity signal beam.[1] Since the switching mechanisms all rely on intensity, any information contained in the phase of a signal beam cannot be used. Here we propose and demonstrate experimentally for the first time a different approach in which a weak beam can switch a strong beam, with the fraction switched controlled by the phase instead of the intensity of the control beam. Picosecond switching based on this idea was implemented in rocking filter fibers.