Abstract

In the last few years, many applications of the ultrafast nonlinearity of semiconductors operated at photon energies below half the band gap have been reported.^1,2 A number of devices, fabricated in AlGaAs and operated at 1550 nm, have been demonstrated, including the nonlinear Mach-Zehnder interferometer,³ the nonlinear X-Junction,⁴ and the nonlinear directional coupler (NLDC)⁵ Nonlinear directional couplers have also been used as demultiplexing elements in two configurations, the first using different polarizations,⁶ and the second using different wavelengths,⁷ for the control and signal. For such nonlinear devices to become practical elements in future all-optical networks, the switching power will have to reduced to an acceptable level. In this paper we present results for an optimized waveguide structure, in which the effective area has been reduced to 6 μm² from 12 μm², with a corresponding decrease in the switching-power requirements.

© 1995 Optical Society of America