Improvement of crosstalk tolerance in optical cross connects by regenerative frequency converters

Crosstalk penalty in optical networks is investigated in a loop experiment at 5 Gbit/s. We demonstrate that in-band crosstalk can be tolerated up to a level of -19.5 dB per cross connect within a penalty of 2 dB (BER=10/sup -9/) for a chain of 5 cross connect paths with regenerative optical frequency converters.