Notice of Retraction: Simple colorless long-reach WDM-PON with rayleigh backscattering noise mitigation employing remodulated orthogonal coding

Abstract

We propose and experimentally demonstrate a novel colorless full-duplex passive optical network architecture with Rayleigh backscattering optical beat interference (OBI) noise mitigation by using orthogonal codes. A pair of orthogonal codes are generated and transmitted from optical line terminal (OLT) to optical network unit (ONU) with the same wavelength, in which, one for downstream signal coding, and the other for the upstream seeding signal. In ONU, the upstream signal is remodulated without erasing the downstream signal. Extra centralized CW light sources and gain-saturation RSOAs are not needed. By using orthogonal codes, the spectral overlap between upstream and downstream signal is reduced, which can mitigate OBI noise significantly. The performance of transmission and power margin are investigated through experiments at different data rates, transmission distances compared with normal on-off keying (OOK) signals. The remodulated upstream signals are correlatively received at OLT with coding gain which is useful in long-reach transmissions. Due to coding gain and OBI noise mitigation, total 4~9dB power margin is achieved for 5Gb/s downstream and 1.25Gb/s upstream with 20km to 70km transmission distances.