Characteristics of nonlinear optical excitation of modes in planar waveguide structures

A theoretical investigation is made of nonlinear excitation of planar waveguide modes at frequencies ω when external plane optical waves of frequency ω₁ are incident on the waveguide surface. The general formulas for the efficiency of the excitation of modes by a monochromatic wave are obtained and analyzed for the case of self-interaction of the ω = ω₁ + ω₁ – ω₁ type and by a biharmonic wave in the case of generation of the difference frequency ω = ω₁ – ω₁'. The efficiency of parametric conversion of waveguide modes ω accompanied by an increase of the frequency to the range ω' is considered for the case when the sum frequency ω + ω₁ = ω₁' is generated. The numerical method developed by the authors is used to analyze the characteristic features of these processes in some specific cases.