Demonstration of a Low-Cost Inband FEC Scheme for STM-64 Transparent Metro Networks

A novel inband forward error correction (FEC) method, developed for the electronic-mitigation of physical optical impairments is implemented and experimentally demonstrated. The proposed inband FEC scheme, FOCUS, is an inherently low-cost approach scalable to any SDH/SONET rate and capable to significantly increase the performance characteristics of metro optical networks. The performance efficiency of the FOCUS method is evaluated in terms of optical signal to noise ratio (OSNR) degradation and chromatic-dispersion degradation associated with the signal transmission over standard single mode fibre. In addition, the system performance is examined using wavelength division multiplexing (WDM) in order to evaluate the effect of nonlinearities. Bit error rate measurements at the standard STM-64 rate (9.953 Gb/s) reveal significant coding-gain improvement for all the examined cases. The benefit of the FOCUS scheme is that it does not require an increased line-rate, as is the case with outband FEC, and therefore offers significant efficiency improvement at an exceptionally low implementation cost