40 Gb/s Single R-SOA Transmission by Optical Equalization and Adaptive OFDM

We report the first demonstration of a 40 Gb/s orthogonal frequency division multiplexing (OFDM) optical system exploiting a common 1 GHz bandwidth R-SOA and direct detection. To this aim, we combined the use of two techniques, i.e., the adaptive OFDM signaling and the optical equalization. Adaptive OFDM (with optimized bit- and power-loading) allowed us to increase the spectral efficiency and the resilience to chromatic dispersion. Optical equalization was obtained by the interplay between the chirped signal produced by the reflective semiconductor optical amplifiers (R-SOA) and a detuned WDM demultiplexer. This allowed us to increase the useful channel bandwidth to > 10 GHz. By this combination and using state of the art A/D and D/A converters, a 40 Gb/s signal is successfully transmitted over a 26 km SMF optical ring.