Modeling of Ti:LiNbO3 Waveguide Devices: Part I—Directional Couplers

We have developed an efficient modeling method to simulate Ti-indiffused LiNbO3channel waveguide devices from their design and fabrication parameters. Procedures are: 1) derivation of the two-dimensional (2-D) refractive index profile; 2) transformation of the 2-D transverse refractive index profile to its one-dimensional (1-D) effective index profile; and 3) use of the 2-D beam propagation method to analyze the device performance. With slight consistent adjustments on Ti-induced refractive index changes, we were able to calculate the performances of directional couplers in good agreement with experimental measurements. This modeling method can be used to predict performance of future devices.