Demonstration of all-optical demultiplexing at 1555 nm with an AlGaAs directional coupler

The authors have demonstrated for the first time femtosecond demultiplexing of signal pulses (500 fs) in an integrated optical nonlinear directional coupler. Its short length relative to fibre devices leads to greatly reduced delay times, and insensitivity to environmental parameters such as temperature gradients etc. With proper device design, the switching can be made essentially complete. Furthermore, other integrated optics designs can he used to reduce further the switching energy from the present 100 pJ.