Optimal power-aware design of all-optical multicasting in wavelength routed networks

Power loss encountered by the optical signal in the light-trees can be due to attenuation, signal splitting, or both. Optical amplifiers may have to be used in order to recover from the power loss so that the optical signal can still be detected at the receivers. Due to the high cost of optical amplifiers, we introduce an optimal power-aware design of wavelength-routed optical networks supporting multicast traffic. The network design problem is formulated as a mixed-integer linear programming, and the main objective is to minimize the total required gain in the network while allowing unequally powered signals. It also determines the optimal number and placement of the splitters, and the routing and wavelength assignment for the multicast sessions. We used the CPLEX linear optimization package in order to solve the MILP formulation. Then, the number and location of optical amplifiers per link is computed off-line.