Design of a Translucent Wide-Area Network

Abstract

In this chapter, we somewhat depart from the fully-transparent environment assumed so far. We acknowledge the fact that a fully transparent wide-area optical network is not feasible due to various signal impairments. The degradation in the signal quality dictates the need for signal regeneration at some strategic locations in the network. In this chapter, we introduce the design problem of dimensioning a given network to provide acceptable bit-error-rate (BER) for all connection demands with the objective of minimizing the cost of various optical and electronic components such as fiber links and regenerator nodes. The problem is non-trivial due to the interference between the optical channels when passing through the same optical amplifier (e.g., Erbium-Doped Fiber Amplifier EDFA). In addition, the aggregate power of all channels cannot exceed some threshold in order to prevent nonlinearity problems. We provide a mathematical formulation of the problem. Due to its difficulty, we propose an algorithmic solution approach. Numerical examples on different network topologies are presented which show the performance of our algorithms compared to obtained bounds when transmission impairment factors are relaxed.