Optimum Design and Characterization of Rare Earth-Doped Fibre Amplifiers by Means of Particle Swarm Optimization Approach

The rapid increasing of internet services requires communication capacity of optical fibre networks. Such a task can be carried out by Er3+-doped fibre amplifiers, which allow to overcome limits of unrelayed communication distances. The development of efficient numerical codes provides an accurate understanding of the optical amplifier behaviour and reliable qualitative and quantitative predictions of the amplifier performance in a large variety of configurations. Therefore, the design and optimization of the optical fibre can benefit of this important tool. This chapter proposes an approach based on the Particle Swarm Optimization (PSO) for the optimal design and the characterization of a photonic crystal fibre amplifier. Such approach is employed to find the optimal parameters maximizing the gain of the amplifier. The comparison with respect to a conventional algorithm shows that the proposed solution provides accurate results. Subsequently, the presented method is used to study the amplifier behaviour by evaluating the curves of optimal fibre length, erbium concentration, gain, and pumping configuration. Finally, the PSO based algorithm is exploited to determine the upconversion parameters corresponding to a desired value of gain. This application is particularly intriguing since it allows recovery of the values of parameters of the optical amplifier, which cannot be directly measured.