A Low-Cost Inband FEC Scheme for SONET/SDH Optical Metro Networks

A novel inband forward-error correction (FEC) method, devised for the electronic-mitigation of physical optical transmission impairments, is implemented and experimentally demonstrated. The proposed inband-FEC scheme, Free-Of-Charge Uniform Shield (FOCUS), is an inherently low-cost approach, applicable to standard synchronous digital hierarchy/synchronous optical network rates, allowing optically transparent signal propagation over longer distances. The performance/efficiency of the FOCUS method is evaluated in terms of tolerance against optical signal-to-noise ratio degradation and chromatic-dispersion, associated with the signal transmission over standard single-mode fiber. Bit-error-rate measurements and coding gain calculations at the standard STM-64 rate (9.953 Gb/s) reveal significant coding-gain improvement for all cases examined