FIT-TD simulation of non-linear materials for second harmonic generation in periodically poled lithiumniobate waveguides

This paper presents a strategy to implement instantaneous χ
⁽²⁾
non-linear materials in the finite integration technique (FIT) in time domain. The extended algorithm is applied to a numerical example consisting of a periodically poled lithiumniobate ridge waveguide used for second harmonic generation (SHG). The results obtained by the simulation are analyzed by a modal technique in order to evaluate the increasing power of the relevant SHG modes.