Abstract

Recent experiments have demonstrated ultrafast all-optical switching with nonlinear glass fiber couplers. Power-induced switching between either two counterrotating circularly polarized modes, linearly coupled by the fiber birefringence¹ or two modes of a dual-core fiber/ coupled through evanescent field overlap, have been reported using picosecond pulses in the normal dispersion regime. Since the inertia of the nonlinear response of glass is of tie order of a few optical cicles, the ultimate limit to the speed of fiber switches will be set by group velocity dispersion. Another important limitation to the use of these devices with ordinary pulses is the fact that a detector slow with respect to the pulse rise time will only measure the energy and not the instantaneous power in the switched pulses. With sufficiently long pulses, one can assume that each individual portion of the pulse profile will evolve according to its input value of power as it would occur for a continuous wave of the same power.

© 1988 Optical Society of America