Modeling, characterization, and experimental/numerical comparison of signal and fluorescence amplification in Ti,Er:LiNbO/sub 3/ waveguides

A complete model for signal and fluorescence amplification in Ti,Er:LiNbO/sub 3/ waveguides under 1480 and 980 nm excitation, which includes transitions involving high energy levels, is presented. Most of the waveguide parameters that the model requires have been determined or checked in situ. In order to numerically solve the proposed model, the overlapping factors method has been adapted to these waveguides and improved, obtaining a large computing time reduction with sufficiently accurate results. Finally, results from signal gain and ASE spectral measurements and numerical simulations have been compared. The remarkable agreement confirms both the model assumptions and the used characterization techniques. Moreover, the unusually short computing time which is consumed makes the model suitable for design and optimization processes.