ANALYSIS OF THE EIGENMODES OF 2 COUPLED TILINBO3 OPTICAL WAVE-GUIDES AND ITS APPLICATION

Two kinds of trial solutions for the symmetric and antisymmetric modes of the parallel Ti:LiNbO3 waveguide structure are proposed and their parameters are determined by use of the variational method. Comparison with the results of the finite-element method are reported experiment al results shows that the solutions composed of Hermite-Gaussian funct ions might achieve better accuracy. It is shown that the formulae esta blished here are suited for both single waveguide structures and coupl ed waveguide structures. In addition, we discuss the optimal electrode design for the symmetric directional coupler switches with a zero wav eguide spacing. It is found that the required drive voltage can be low ered by choosing a small electrode gap and an appropriate electrode wi dth.