All-optical switching with pulsed signals in an all-semiconductor-optical-amplifier loop device

Picosecond pulsed-signal operation for efficient self- and cross-switching in an all-semiconductor-optical-amplifier loop device was implemented. Although the configuration of the device is similar to a conventional nonlinear optical loop mirror, the operation principles are quite different. For cw signals, the device operation relies on the nonlinear coupling effect in a multi-mode interference waveguide amplifier and the lateral field redistribution and amplification by the active loop. However, for pulsed signals the crucial factor of asymmetric gain distribution in the loop needs to be added for the device operation. The pump-probe experiments provided efficient cross-switching results and indicated that GHz-range operation is feasible by redesigning the device configuration for pump signal injection. (C) 2000 Elsevier Science B.V. All rights reserved.