THEORETICAL MODELING OF OPTICAL AMPLIFICATION IN ER-DOPED TI-LINBO3 WAVE-GUIDES

An accurate theoretical analysis is presented describing optical amplification in Er-diffused Ti:LiNbO3 channel waveguides. It follows as far as possible the theory already developed for Er-doped fibers. As optical pumping around lambda(p) almost-equal-to 1.48 mum is considered, a quasi-two-level model for the Er3+ ions is used with wavelength-dependent cross sections. The optical gain in the 1.53 mum < lambda < 1.64-mum wavelength range is evaluated. The characteristic parameters, as Er concentration profile, cross sections, pump, and signal mode distributions and waveguide (scattering) losses are taken from experiments. Examples of numerically calculated pump-, small-signal-gain-, and ASE-evolutions are presented. The model has been tested by comparing computed and experimentally observed gain characteristics for X- and Z-cut LiNbO3; an almost quantitative agreement has been obtained.