All improved semiconductor optical amplifier for ultrafast all-optical signal processing

The use of semiconductor optical amplifiers (SOAs) as optical nonlinear elements has had a profound effect on the field of all-optical signal processing for telecommunications applications. The invention of the TOAD (terahertz all-optical asymmetric demultiplexer), and the subsequent discovery that switching rates much faster than the natural recovery rate of the SOA are possible, has allowed all-optical demultiplexing at high switching rates (>1OGHz). In the paper we use a SOA which has been designed to have a larger band-gap than usual, having a gain peak at /spl sim/1500 nm. This improves the both the contrast ratio and the amplitude modulation associated with TOAD arrangement.