Quasistatic analysis of coupled coplanar waveguide traveling-wave electrodes for electro-optic modulators

In this letter, an LiNbO3 optical modulator using a coupled coplanar waveguide (CPW) with an SiO2 buffer layer is analyzed accurately by incorporating the traveling-wave electrode thickness effect. The effect of coupled ground planes, electrode, and buffer layer thickness on the effective dielectric constant and characteristic impedance of coupled CPW electrode is discussed. Numerical computations show that increasing the width of the coupled ground planes can slightly improve the phase velocity mismatch between electric and optical waves. (C) 1999 John Wiley & Sons, Inc.