Simple analytical equations, representing power distributions in a propagation direction for a Cerenkov-type SHG, were derived. Using this model, dependence of conversion efficiency on propagation loss has been analyzed. Waveguide loss affects the beam profile of the output second harmonic wave, as well as the conversion efficiency. The power distribution in an external-resonant-cavity configuration can be treated by this model. The waveguide loss effect is more conspicuous for the cavity-type SHG.

Cerenkov-type SHG has been analyzed using analytical solution of nonlinear wave equation. It was found that the conversion efficiency is strongly affected by the waveguide layer structure. This is considered to originate in a kind of phase-mismatching in a direction perpendicular to the waveguide plane, although the phase-matching condition in the propagation direction is satisfied. The conversion efficiency is reduced by cancellation effect, when the guide layer and the substrate have same-sign nonlinear coefficients.

Thermal properties of InGaAlP laser diodes have been analyzed by computer simulation. Self-consistent analysis considering heat conduction, current distribution and optical waveguide mode has made it clear that there exist optimum structural parameters minimizing the threshold current.