Comparison of DWDM Network Topologies with Bit-Rate Adaptive Optical OFDM regarding Restoration

4 different core networks - including EU and US - are studied for bit-rate adaptive opticalOFDM w.r.t. restoration. The gained benefit over fixed bit-rate 40 Gb/s networks is found to be strongly mean path-length/mean connectivity dependent and reaches up to 42 % savings on OE-interfaces. Introduction Rapid increasing demand of capacity requires higher flexibility and transparency of future DWDM photonic network. So far mainly single line-rate based networks have been deployed but new emerging applications (IPTV, VOD, etc.) lead to more heterogeneous traffic demands. Networks based on mixed line rates (MLR) like 10G/40G or 10G/40G/100G were 1,2 proposed , but these coarse granularities offer low possibilities to adapt to network changes rising up from traffic demands, link failures, physical impairments along a path, etc. Even more, the MLR transponders are located at distinct network nodes. Optical OFDM is a promising candidate for high capacity transmission networks with high flexibility, as the digital processing in transmitter and receiver allows to easily adapt the signal properties (e.g. bit-rate, modulation format, etc.) to network constraints such as reach, OSNR or traffic demand. Recently, it was shown that bitrate adaptive networks show improved performance regarding required hardware equipment and wavelengths over fixed rate 3-5 solutions . In this paper, we analyze the impact of bitrate adaptive transponders in translucent dynamic networks looking at dynamics of single link failure and restoration, which is one of the most important issues in photonic networks.