用有效折射率／有限元法设计1．55μmTi：LiNbO_3单模条波导及其方向耦合器

DESIGNλ=1. 55μm Ti: LiNbO_3 SINGLE-MODE STRIPE WAVEGUIDES AND DIRECTIONAL COUPLERS WITH EI-FEM

应用有效折射率／有限元法（ＥＩ－ＦＥＭ），考虑到ＬｉＮｂＯ３晶体和Ｔｉ扩散的各向异性，折射率增量与寻常光、非寻常光及波长色散的关系，设计了１．５５μｍ光波长下工作的ｚ切ｙ传播Ｔｉ：ＬｉＮｂＯ３单模条波导的制备参数，计算和分析了其单模特性、模式场分布及其变化规律．扩展了ＥＩ－ＦＥＭ，将其用于求解耦合波导系统，确定了方向耦合器的耦合长度及其波长色散特性．

n this paper, the effective index-finite element method (EI-FEM) is employed to design the fabrication parameters for z-cut, y-propagation Ti :LiNbO3 single-mode stripe waveguides at the operation wavelengthλ=1. 55μm. The mode characteristics and the mode field distributions are also calculated and analyzed. Then, the EI-FEM is further developed for calculating the coupling length and it' s wavelength sensitivity of Ti:LiNbO3 waveguide directional couplers.