Ultra-Long-Reach Systems, Optical Transparency, and Networks

This paper examines the interaction between ultra-long-reach (ULR) transmission systems, network architecture, and optical transparency. Maximal transparency requires large regenerator spacings, beyond 20000 Km in North-American continental-scale networks. Smaller spacings (1000 Km) can be used, at the expense of routing restrictions, or opacity. Novel network optimizations on one opaque (OPAQUE) and two partially transparent architectures (LINKOPT, NODEOPT), shows that ULR systems with spacings exceeding 1000 Km are cost-effective for long-distance traffic on sparse continental backbones. Rings with OADM's can benefit from higher spacings.