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 using SiO 2 optical "bres, analysis of non-linear absorption is required. We propose 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 susceptibility and the refractive index with microscopic parameters is provided. To solve the non-linear model for absorption experimental parameters are used. Our results estimate that the average value over the solar spectrum for the non-linear extinction coe$cient for SiO 2 is k 2 "10~29 m2 V~2. With this result we conclude that the non-linear part of the absorption coe$cient of SiO 2 optical "bres during the transport of concentrated solar energy achieved by a circular concentrator is negligible. ( 2000 Elsevier Science B.V. All rights reserved.