Optimization Problems in Optical Networks

The huge potential of optical networks for satisfying the skyrocketing needs of broadband telecommunication services while meeting rigid quality of service requirements has long been acknowledged. However, although fiber has become the medium of choice in telecommunication networks, its vast resources are severely under-used, due to the much slower electronics that are interfaced with the optical medium. For instance, transceivers operate at speeds that are several orders of magnitude below the actual usable capacity of the fiber (several Gbps versus hundreds of Gbps). In order to achieve higher rates, Wavelength Division Multiplexing (WDM) techniques have been widely suggested. The concept behind WDM is to partition the optical spectrum into multiple non-overlapping wavelength channels, each modulated at electronic speed. WDM networks offer potential advantages, including higher aggregate bandwidth per fiber, new flexibility for automated network management and control, noise immunity, transparency to different data formats and protocols, low bit-error rates, and better network configurability and survivability-all leading to more cost-effective networks.