Non-linear model for absorption in SiO2 optical fibres: Transport of concentrated solar energy

In order to determine the maximum solar energy than can be transported usin g SiO2 optical fibres, analysis of non-linear absorption is required. We pr opose a model based on Maxwell's equations and the Drude-Lorentz theory to determine the non-linear absorption for the maximum possible concentration ratio for circular concentrators. The relation between the electric suscept ibility and the refractive index with microscopic parameters is provided. T o solve the non-linear model for absorption experimental parameters are use d. Our results estimate that the average value over the solar spectrum for the non linear extinction coefficient for SiO2 is k(2) = 10(-29) m(2) V-2. With this result we conclude that the non-linear part of the absorption coe fficient of SiO2 optical fibres during the transport of concentrated solar energy achieved by a circular concentrator is negligible. (C) 2000 Elsevier Science B.V. All rights reserved.