Distributed ultradense optical frequency-division multiplexing using fiber nonlinearity

We extend our investigations on a recently proposed concept for distributed coherent optical orthogonal frequency-division multiplexing (CO-OFDM) by fiber-frequency conversion for locally defined exact channel mapping based on free-running lasers. Experiments with quadrature phase-shift keying and 16-quadrature amplitude modulation subchannels show error-free performance and are compared to experiments with locally generated CO-OFDM.