Optimization of SOA-based Sagnac-interferometer switches for demultiplexing to 10 and 40 Gb/s

We investigate the performance of a semiconductor optical amplifier (SOA) b ased Sagnac-interferometer switch in its application as time division demul tiplexer. By performing dynamic switching window measurements with a time r esolution of about 1 ps, the temporal width and the contrast of the switchi ng windows are investigated for SOA lengths of 5001 1000 and 1500 mum. Oper ating the switch with a control pulse rate of 10 GHz (corresponding to all- optical demultiplexing to 10 Gb/s) the shortest switching windows, still re taining high contrast, are achieved with short SOAs. By increasing the cont rol pulse rate to 40 GHz. the case of an SOA-based all-optical demultiplexe r with a base rate of 40 Gb/s is investigated. Though the switching contras t deteriorates for the 40 GHz control pulse rate, the obtainable contrast i s still up to 19 dB. This finding encourages the feasibility of SOA-based i nterferometric demultiplexers with base rates of 40 Gb/s. In particular, th is feature will be crucial to future all-optical demultiplexers as the base rate of electronic signal processing is currently evolving to 40 Gb/s. (C) 2001 Elsevier Science B.V. All rights reserved.