DSP methods for the evolution from conventional TDM-PON to DSP-enhanced TDM -PON

Recently, digital signal processing (DSP) methods have attracted a lot of attention for next-generation passive optical network (PON). To achieve high spectrum-efficiency colorless transmission, we combine the time-division-multiplexing (TDM) architecture with advanced DSP methods to propose a DSP-enhanced TDM-PON, in which DSP-based symbols are transmitted in different time slots instead of on-off-key (OOK) bits in conventional TDM-PON. Four DSP methods with frequency-domain equalization (FDE) are discussed in terms of computational complexity, peak-to-average ratio (PAPR), and flexibility. A DSP-based evolution scheme from conventional TDM-PON to DSP-enhanced TDM-PON is proposed and experimentally demonstrated by upgrading the optical line terminal (OLT) to support both OOK and DSP-based signals, which can maintain the current optical distribution network (ODN) and minimize the impact for the existing service and equipment.