Opto-Electronic and All-Optical Wavelength Translators and Their Cascadability

Cascadability of bit rate transparent opto-electronic and all-optical translators is measured by a re-circulating loop testbed. The all-optical translators are implemented through monolithic integration of semiconductor optical amplifiers and Mach-Zehnder or Michelson interferometers. Both the OEO and all-optical translators are capable of converting 10 Gbit/s signals. However, the all-optical translators have demonstrated superior cascadability performance compared to the opto-electronic translators. More than 30 all-optical translators can be cascaded whereas only 7 OEO-translators with a bandwidth of 4 times the bit rate (2.5 Gbit/s) can be cascaded. Decreasing the bandwidth of the OEO translator decreases further the number of cascadable translators. The excellent cascadability performance of the all-optical translators compared to OEOs is attributed to the flat amplitude and phase transfer function of the former.