A surface waveguide is disclosed. In the illustrative embodiment, the waveguide has a core and an upper and lower cladding. The core has a thickness that is greater than the critical thickness of the material that composes the core. This is achieved by depositing/growing the core as a conformal layer within a region that is recessed from the planar surface of the lower cladding, wherein the recessed region has a width that is no more than twice the critical thickness of the core material.