Direct modulation and coherent detection optical OFDM

Optical orthogonal frequency division multiplexing (O-OFDM) with a novel direct modulation and coherent detection system at 34.3 Gb/s and 16 QAM is proposed. Electronic pre-compensation of laser frequency response is applied at the transmitter. Following homodyne coherent detection and analog to digital conversion, digital signal processing compensates the DFB laser frequency chirp and chromatic dispersion (CD). Mathematical results and numerical simulation show that the proposed system achieves 10^-3 BER with 10.5 E_b/N₀, similar to a standard single carrier system.