Transmission transparency and potential convergence of optical network solutions at the physical layer for bit rates from 2.5 Gb·s-1 to 256 Gb·s-1

Abstract

In this paper, we investigate optical network recommendations GPON and XG-PON with triple-play services in terms of physical reach, number of subscribers, transceiver design, modulation format and implementation cost. Despite trends to increase the bit rate from 2.5 Gb s􀀀1 to 10 Gb s􀀀1 and beyond, TDMPONs cannot cope with bandwidth requirements of future networks. TDM and WDM techniques can be combined, resulting in improved scalability. Longer physical reach can be achieved by deploying active network elements within the transmission path. We investigate these options by considering their potential coexistence at the physical layer. Subsequently, we analyse the upgrade of optical channels to 100 Gb s􀀀1 and 256 Gb s􀀀1 by using advanced modulation formats, which combine polarization division multiplexing with coherent detection and digital signal processing. We show that PDMQPSK format is suitable for 100 Gb s􀀀1 systems and PDM-16QAM is more beneficial at 256 Gb s􀀀1. Simulations are performed in the OptSim software environment.