Schemes integrating inter-carrier interference(ICI) self-cancellation and common phase error(CPE) compensation for coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems are investigated.The purpose of our research is to counteract the impacts of laser phase noise and fiber nonlinearity.We propose two ICI self-cancellation-based CO-OFDM schemes,and adopt a pilot-aided decision feedback(DFB) loop for CPE compensation.The proposed schemes are compared with conventional CO-OFDM schemes at the same spectral efficiency.Simulations show that our schemes can not only enhance laser linewidth tolerance of the CO-OFDM system,but also present strong robustness against fiber nonlinearity.
Orthogonal frequency division multiplexing-passive optical network (OFDM-PON) and single-carrier fre-quency division multiplexing (SCFDM)-PON are promising solutions for future high-speed PON-based access. A polarization division multiplexing scheme with direct detection is proposed for OFDM-PON to effectively reduce bandwidth requirements for components. However, the scheme strictly requires spec-trum overlapping of two orthogonal sidebands and the 4×4 multi-input-multi-output (MIMO) algorithm to eliminate complex cross-polarization interference. In this letter, we propose a polarization interleaving (PI) approach that significantly reduces bandwidth requirements for optical and electrical components while achieving a high-flexibility and low-complexity MIMO algorithm. Downstream single sideband PI-SCFDM transmission is experimentally demonstrated.
