Real-time transmission of 3 Gb/s 16-QAM encoded optical OFDM signals over 75 km SMFs with negative power penalties.

Real-time optical orthogonal frequency division multiplexing (OOFDM) transceivers are experimentally demonstrated with advanced pilot subcarrier-assisted channel estimation being implemented. The channel estimation technique is, for the first time, proposed and experimentally verified rigorously, which offers a number of unique features including high accuracy, low complexity, small pilot bandwidth usage, excellent stability and buffer-free data flow. The fastest ever real-time end-to-end transmission of 3 Gb/s 16-QAM-encoded OOFDM signals over 75 km MetroCor single-mode fibres is achieved with negative power penalties of -2dB at BERs of 1.0 x 10(-4) in directly modulated DFB laser-based, intensity-modulation and direct-detection systems without in-line optical amplification and chromatic dispersion compensation.