Method for calculating coupling length of Ti:LiNbO/sub 3/ waveguide directional couplers

Reports a theory for calculating the coupling length L/sub c/ of Ti:LiNbO/sub 3/ single-mode waveguide directional couplers from process parameters and operating wavelength. Estimates are accurate to within a factor of 2 compared with published experimental results for z-cut y-propagating LiNbO/sub 3/ devices for 0.63 mu m>