TDM-PON with 30 Gb/s D8PSK downstream and 10 Gb/s OOK upstream based on a digital incoherent receiver

In this paper, we propose the use of multilevel modulation formats with differential detection to enable Next-Generation Time-Division Multiplexing Passive Optical Networks (TDM-PONs). Bidirectional transmission of 30 Gb/s Differential 8 Phase-Shift Keying (D8PSK), on the downstream, and 10 Gb/s On-Off Keying (OOK), on the upstream, over a TDM-PON has been demonstrated experimentally. Furthermore, some of the functionalities that can be implemented in Digital Signal Processing (DSP) in the receiver, namely wavelength misalignment compensation, IQ imbalance mitigation and data-aided multiple symbol phase estimation, are explored. Results indicate that DSP-based incoherent multilevel formats are an attractive option for providing the high bit rates required for future TDM-PONs.