The present invention relates generally to wavelength conversion devices and laser projection systems incorporating the same. According to one embodiment of the present invention, wavelength conversion devices are provided without limitation of their field of use to laser projection systems. For example, the wavelength conversion device may comprise an axial waveguide portion and a pair of lateral planar waveguide portions confined between a pair of relatively low index cladding layers. The effective index of refraction in the axial waveguide portion of the waveguide region and the effective index of refraction in the lateral planar waveguide portions of the waveguide region are established such that the relatively low intensity laterally distributed parasitic light is characterized by a scattering angle θ that is at least as large as the beam divergence angle of the relatively high intensity light propagating in the axial waveguide portion.