day, the open research line for groups studying optical packet switching is to concen- trate on what happens at very high bit rates, like 800 Gbit/s, where even multilevel trans- mission with a great number of levels does not reduce the bandwidth SO much as to render electronics more competitive. It is not clear if such systems (transmission and switches) will be introduced following a clear market request and when it will happen, but the history of photonics up to now has always demonstrated that increasing the bit rate over the single wavelength is beneficial from a CAPEX point of view. It is out of the scope of this book even to review all the experiments where different meth- ods have been proposed to multiply and demultiply, with optical means, very high bit rate channels and have also introduced all-optical node architectures suitable for this scope. The interested reader is encouraged to access the literature on this subject, starting with [81-83]. Next Generation Networking: Enabling Technologies, Architectures, and Performances References 1. Melle, S., Building agile optical networks, Optical Fiber Communications Conference-OFC 2008, San Diego, CA, paper NME2, March 2008. 2. Iannone, E., Next generation wired access: Architecture and technologies. In K. Iniewski (Ed.) Internet Networks, Taylor & Francis, Boca Raton, FL, s.l., 2010. 3. Hurtt, S. et al., The first commercial large-scale InP photonic integrated circuits: Current status and performance, 65th Annual Device Research Conference, South Bend, IN, IEEE, s.l., p. 183, June 18-20, 2007. 4. Joyner, C. et al., Current view of large scale photonic integrated circuits on indium phosphide, Optical Fiber Communication Conference, OFC 2010, San Diego, CA, IEEE, s.l., p. paper OWD3, March 21-25, 2010. 5. Cochrane, P., Heckingbottom, R., Heatley, D., The hidden benefits of optical transparency, IEEE Communication Magazine, 32(9), 90-97 (1994). 6. Carpenter, T. et al., Maximizing the transparency advantage in optical networks, Optical Fiber Communication Conf