Abstract

All-optical switching devices may play an important role in future highspeed communications systems. Recently we demonstrated switching of 100-fsec pulses by a dual-core fiber all-optical switch [1]. One problem associated with short pulse operation of the dual-core fiber switch, or any all-optical switch triggered by instantaneous intensity, is pulse break-up: switching can occur within a pulse, so that low and high intensity portions of the same pulse are directed to different output ports [1,2]. Proposals have been made to solve the pulse break-up problem by using solitons [3]. A simpler solution is to use square optical pulses, in which the intensity across the pulse is constant, except for finite rise and fall times. Here we report the first application of femtosecond square pulses to avoid pulse break-up in alloptical switching. As a result we obtain enhanced power transfer and a sharper switching transition.

© 1989 Optical Society of America