Tilted traveling wave electrodes and impacts on high-speed operation of integrated electro-optic modulators: modeling and experimental demonstration

Broadband optical modulators, especially the LiNbO3 interferometric types, are currently important in the generation of advanced modulation formats for operating bit rate in the 100 Gb/s range for 100-Gb/s optical Ethernet networks. In these devices the effectiveness of generation of the traveling electric field for electro-optic interaction is very critical. This work presents the modeling of the tilted wall of traveling wave electrodes and their impacts on the operating bandwidth over interferometric optical waveguide structures and modulators. The effects of the tilt of thick electroplated electrodes on the device bandwidth are significant. The electro-optic overlap integral can be evaluated with tilt electrodes. Key features for optimization of the electro-optic overlap integral are studied to realize modulators of low half-wave driving voltage and fabrication of optical modulators under limited etching facility. Experimental demonstration of the effects of tilted electrodes on the performance of a Mach-Zehnder interferometric modulator is given to confirm simulation results. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3231504]