The growing data traffic in the local area networks is driving development of the cost-effective transmission systems that can carry it effectively. In this study, firstly, we investigate the influence of a semiconductor optical amplifier (SOA) on the transmission quality in the 1310 nm wavelength-division-multiplexed system. We examine the differences in the channels gain and power penalty depending on the applied channel spacing. Moreover, we analyse the transmission-related power penalty suffered during the transmission over the link consisting of the standard single-mode fibre (SSMF) and a SOA. Furthermore, we propose the 1310 nm dense-wavelength-division multiplexed and polarisation multiplexed transmission system architecture which co...