An optical modulator including a substrate made of lithium niobate having an electrooptical effect, first and second optical waveguides formed in the substrate by effecting a thermal diffusion of titanium into a surface of the substrate, a buffer layer formed on the surface of the substrate, a hot...http://www.google.de/patents/US5748358?utm_source=gb-gplus-sharePatent US5748358 - Optical modulator with optical waveguide and traveling-wave type electrodes 
