Title :
Optimum design of coplanar waveguide for LiNbO3 optical modulator
Author :
Zhang, Xiang ; Miyoshi, Tanroku
Author_Institution :
Dept. of Electr. & Electron. Eng., Kobe Univ., Japan
fDate :
3/1/1995 12:00:00 AM
Abstract :
In this paper, we first present a novel finite element method combined with the conformal mapping (FEM-CM) for a quasi-static analysis of coplanar waveguides (CPW). Using this approach, the optimum CPW structures for the use in the Ti:LiNbO3 optical modulator are discussed in detail to realize optical-microwave phase velocity match and electrode-source characteristic impedance match. Our numerical results reveal that both conditions can be satisfied simultaneously by introducing a SiO2 buffer layer and thicker electrodes. The modulator efficiency with respect to the voltage-length product is also evaluated for the optimized structures. Finally, the design guidelines to the optimum CPW structure are presented
Keywords :
coplanar waveguides; electro-optical modulation; finite element analysis; lithium compounds; optical communication equipment; optical planar waveguides; optical waveguide components; titanium; CPW structures; LiNbO3:Ti; LiNbO3:Ti-SiO2; conformal mapping; coplanar waveguide; design guidelines; electrode thickness; electrode-source characteristic impedance match; finite element method; modulator efficiency; optical modulator; optical-microwave phase velocity match; quasi-static analysis; voltage-length product; Buffer layers; Conformal mapping; Coplanar waveguides; Electrodes; Finite element methods; Impedance; Optical buffering; Optical modulation; Optical waveguides; Phase modulation;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
