Solutions for a single carrier 40 Gbit/s downstream long-reach passive optical network

This paper presents a single carrier 40 Gbit/s downstream long-reach passive optical network (LR-PON) topology as candidate for upgrading current fiber infrastructure towards higher data rates. A 100 km LR-PON network was investigated and 2 solutions to overcome chromatic dispersion were proposed. Firstly, a dispersion compensated element is added to compensate the mean length of the feeder fiber. Secondly, an advanced modulation scheme, i.e. 3-level electrical duo-binary is introduced. This scheme has the advantage of allowing lower bandwidth APDs and requires only limited additional electronics. Furthermore, to overcome the inherent discrepancy between aggregated line rate and user rate, and hence the reduced power effciency, the BiPON protocol is added to minimize signal processing at the high line rates.