Transmission of sub-carrier multiplexed analog signals through the optical transport network

The technical advances in wavelength division multiplexing (WDM) techniques has made possible the introduction of optical technology into the path layer of the transport network. Besides the significant improvement in the transmission capacity, WDM technology allows the accomplishment of routing and switching functions directly in the optical domain. Thus Optical Cross-Connects (OXCs) can be realized with a throughput of a few hundreds of Gbit/s, so removing the bottleneck placed by electronic technology. The transport network node can be designed as an OXC interfacing a Digital Cross-Connect (DXC). Multi-Gigabit signals are directly routed in the optical network layer by the OXCs, while the DXCs provide demultiplexing to lower digital hierarchies and routing at the electrical level. The optical path layer can be designed so as to be transparent to the signal transmission format and speed. The aim of this paper is to assess the feasibility of transmitting sub-carrier multiplexed CATV channels in this optical path layer, by analysing the performance of the following transmission path: the CATV channels are generated in a production center, cross a geographical area through a transport network and an optical ring of a regional network, down to the access network and then to the customer.