Ultra-Dense, Single-Wavelength DFT-Spread OFDMA PON With Laserless 1.2 Gb/s ONU Ready for Silicon Photonics Integration

We introduce an ultra-dense network architecture designed for silicon photonics at the optical network unit (ONU). This network relies on only 3.333 GSa/s and 417 MSa/s converters at the OLT and ONU, respectively, and offers up to 12 Gbit/s of symmetric traffic in a single 12.5-GHz optical channel. Multiple access and lowest processing speeds at the ONU are enabled by choosing 10 DFT-spread OFDM subbands. We demonstrate this FDMA network architecture in a proof-of-principle experiment with up to eight 300-MBd 16QAM subbands offering a bidirectional data rate of 9.6 Gb/s. Real-time signal processing is realized for downstream transmission. Finally, we shortly address future improvements of this network architecture by employing integrated silicon photonics and analog signal processing to enable fine FDM for next-generation access networks.