Abstract
The nonlinear Bit Error Rate (BER) performance of dense Wavelength Division Multiplexed (WDM) Manhattan Street Networks with deflection routing was obtained using a semi-analytical model. The chapter's results show that nonlinear effects impose significant performance penalties on dense WDM networks, both in terms of maximum hops attainable and average BER, and should be taken into account when modeling such networks. Simple techniques such as optimal amplifier positioning can mitigate some of the nonlinear penalties.