Hybrid Modulated Multiband Coherent Optical OFDM for Low-Complexity Phase Noise Compensation

In this paper, we propose and demonstrate effective laser phase noise compensation for coherent optical orthogonal frequency-division multiplexing (OFDM) systems that have long OFDM symbols. The phase noise compensation is achieved via hybrid modulated multiband optical OFDM, aided by the digital filter bank technique. For this, one of the multiple subbands is modulated as discrete Fourier transform spread OFDM. Our experimental results show that laser phase noise up to 1 MHz can be compensated for 114.8-Gb/s 16-QAM signals with 480-km standard single mode fiber transmission.