a method to form a waveguide taper includes forming a core layer on a cladding layer . a protective layer with an opening is formed on the core layer , the opening exposing a portion of the core layer . a cmp process is performed so that dishing occurs in the exposed portion , forming a depression with a sloped sidewall . in one embodiment , the core layer is then patterned so that a portion of the core layer is removed to about the depth of the depression . this removed portion includes a part of the core layer containing the depression . the resulting structure includes an unetched sloped surface that transitions to a substantially planar etched surface . the core layer is patterned and etched again to form the waveguide , with the sloped surface forming part of the taper .