Active branching waveguide modulator

We report the observation of electrically controlled modulation in a single-mode channel waveguide branch fabricated on Ti-diffused LiNbO3. Over 55% intensity modulation has been observed for applied voltages of ±30 V with an active length of 2.9 mm. Experimental factors limiting device performance are discussed. A theoretical description of the device, based on power transfer between local normal modes, is presented and shown to be consistent with experimental results when sideways diffusion in the channels is approximately accounted for.