The finite element analysis and design of a traveling-wave optical modulator based on LiNbO3 fibers

A novel type of LiNbO₃ traveling-wave optical modulator based on LiNbO₃ rectangular fibers is presented in this paper. Compared with traditional LiNbO₃ traveling-wave optical modulator based on LiNbO₃ waveguides, it can make the velocity matching more easily to implement and in result expand the modulating bandwidth which reaches as far as 200 GHz, and also get the impedance of the modulator match well with the source and the load, and the resulting voltage standing wave ratio is approximately 1 by adding two dielectric overlay layers on the electrodes. The dimension of the modulator is analyzed and optimized by finite element method (FEM), and a good result is gained. In the end, the arts and crafts of the interferometer based on LiNbO₃ rectangular fibers, which is the key part of the modulator, are discussed.