Quasi-ideal optical decision characteristic from a Mach-Zehnder interferometer with gain-clamped semiconductor optical amplifiers

We have presented quasi-ideal optical decision characteristics, measured on a Mach-Zehnder interferometer with gain coupled semiconductor optical amplifiers (GCSOAs) in both arms. The decision characteristic has an adjustable threshold and exhibits a very sharp transition between low and high output power. Dynamic measurements at 2.5 Gbit/s demonstrate the regeneration capability even for very small extinction ratios of the input signal: e.g. 7 dB improvement in extinction ratio has been obtained for an input extinction ratio of ∼2 dB, and 6 dB improvement for an input extinction ratio of 1 dB. Therefore, taking the simplicity of the device and the excellent regeneration characteristic into account, this approach is a promising technique for 2R all-optical regeneration.