Wavelength-reused ONUs for next-generation optical WDM/OFDMA-PON

In this paper, we discuss recent progress in orthogonal frequency division multiplexing (OFDM)-based passive optical networks (PON) in a wavelength-reused optical network unit (ONU). To fully regenerate the uplink OFDMA and avoid large bandwidth of analog-to-digital converters (ADCs), a coherent receiver with selected sub-band technique is demonstrated.