An integrated planar waveguide system including at least two primary waveguides for light propagation and coupling, and two or more mirror-imaged symmetrization structures in close proximity to the primary waveguides in order to provide micro-process-equalization during etch, growth, annealing and reflow processes. The primary waveguides are designed to carry light signals. The symmetrization waveguide structures are designed so that all the trenches between primary waveguides are identical to the desired degree. At the same time, the symmetrization structures are designed to have minimal detrimental impact on the optical performance of the coupler.