Abstract: | A model is presented that calculates the features of Cerenkov second-harmonic generation (SHG) in planar dielectric waveguides with an arbitrary index profile. These waveguides are represented by a stack of homogeneous layers of biaxially birefringent media. The model describes type I SHG in channel waveguides within a few approximations, such as the assumption of a quasi-slab channel geometry. Furthermore, this study comprises results of previous step-index models given in the literature, as a particular case of a one-layer structure. These results are in close agreement with measurements of the SHG efficiency in Rb-exchanged erfc waveguides in KTP materials, and in proton-exchanged step waveguides in LiNbO3 as functions of the pump wavelength |