Throughput enhancement of slow adaptive orthogonal frequency division multiple access based passive optical network uplink transmission in 20-km single fibre loopback link employing channel stabilisation

The authors have proposed and experimentally demonstrated a novel slow adaptive orthogonal frequency division multiple access (OFDMA)-based passive optical network (PON) uplink transmission scheme using a 1-GHz reflective semiconductor optical amplifier operating as an optical network unit (ONU) in combination with Rayleigh backscattering (RB) mitigation in a 20-km single fibre loopback link. This RB mitigation, which can dramatically stabilise the channel state information and enhance the total throughput so that the OFDMA-PON transmitters can operate in the slow adaptive concept and provides beyond 15-Gbit/s uplink transmission, is achieved by employing 10-MHz low-frequency dithering of an optical seed carrier cooperating with a gain-saturated semiconductor optical amplifier at an optical line terminal. In doing so, the proposed scheme could guarantee a 50% total throughput enhancement with a proof-of-concept multiple access scenario for two ONUs, compared to its counterpart that does not apply the RB mitigation technique.