294 CHAPTER 10 Challenges for long-haul dynamic Networks The scenario outlined here is still years away, but there is a lot of research going on to ultimately make it happen. 10.4 SUMMARY Optical networks have evolved and continue to evolve in ways that are more and more challenging for the system designers. In large photonic mesh networks, the amplifiers must account for both static and dynamic behavior of the transmission line and accommodate changes without disturbing the traffic quality of service. As more traffic at higher bit rates is placed on these networks, survivability in the face of upstream failures becomes even more important, and the design and control can differentiate one solution from another. Carriers are looking for solutions that have been designed and tested against all possible failure scenarios and can handle network additions and deletions seamlessly. Finally, it is desirable to have a true photonic mesh-restorable network where wavelengths can be treated the same way as the electrical bandwidth and protected in a shared way against catastrophic failure. ACRONYMS DCM DEMUX DWDM IP ITU MUX OSNR ROADM SONET SRS ULH WDM Dispersion compensation modules Demultiplexer Dense wavelength division multiplexing Internet protocol International Telecommunication Union Multiplexer Optical signal-to-noise ratio Reconfigurable optical add/drop multiplexer Synchronous optical network Stimulated Raman scattering Ultra-long-haul Wavelength division multiplexing References [1] J. Berthold, A.A.M. Saleh, L. Blair, J.M. Simmons, Optical Networking: Past, Present, and Future, Journal of Lightwave Technology 26 (9) (2008) 1104e1118. [2] A.A.M. Saleh, Overview of MONET project, Lasers and Electro-Optics. CLEO/ Pacific Rim '97., Pacific Rim Conference, July 14e18, (1997) pp. 12e12