A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the...http://www.google.de/patents/US20050031284?utm_source=gb-gplus-sharePatent US20050031284 - Waveguide for thermo optic device