title: Level coding technique for a wavelength-division-multiplexed optical access system using a remodulation scheme.
abstract: In the wavelength-division-multiplexed optical access network, the system architecture based on remodulating the downstream (DS) signal for upstream transmission resolves the issues of wavelength management and hardware cost . However, this amplitude remodulation scheme introduces intensity noise in the uplink and leads to a system performance penalty. Therefore, the DS extinction ratio (ER(d)) has to be optimized in order to balance the performance of up- and down- links. In this Letter, a novel technique is presented to overcome the restrictions on ER(d) by introducing correlations into the levels of the DS signal to alter its spectrum. 4 dB improved tolerance to ER(d) is achieved in the proposed system. The level-correlation coding technique is also able to mitigate the in-band crosstalk induced by Rayleigh backscattering. It is demonstrated that the system reach is extended by 40 km with the proposed approach.
authors.affiliation: Victoria Research Laboratory, National ICT Australia, Level 2, Electrical and Electronic Engineering, University of Melbourne, Parkville, Victoria 3010, Australia. q.guo@pgrad.unimelb.edu.au
authors.forename: Qi
authors.initials: Q
authors.lastname: Guo
authors.forename: An V
authors.initials: AV
authors.lastname: Tran