Contents I. Introduction
There has been a sharp increase in demand for high speed access services [1] with passive optical networks (PONs) offering a route to accommodating this level of growth economically [2] [3] [4]. While the current standard specifies a specific margin, PONs exhibiting improved system margins are crucial since they provide increased reach and/or enhanced splitting ratios. This evolution necessitates the use of amplification and given these systems use 1490nm downstream and 1310nm upstream, semiconductor optical amplifiers (SOAs) have a clear role to play. Reflective Semiconductor Optical Amplifiers (RSOAs) are also relevant to future PONs architectures providing a colourless amplifier obviating the need for tuneable of fixed laser sources at the customer premises. The RSOA can be seeded with a single continuous wave source shared among a number of users and can simultaneously amplify and modulate that seed to support a WDM overlay on the PON in a wavelength agnostic manner.
