Analysis of Linear and Nonlinear MQW Semiconductor Optical Waveguides

• Main Authors: Chuang, Guo Chen, 莊國禎
• Other Authors: Chang H. C.
• Format: Others
• Language: en_US
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/22514645695119755885

碩士 === 國立臺灣大學 === 電機工程學系 === 86 === The finite element (FEM) is used to theoretically investigate the propagation characteristics of both linear and nonlinear multiple quantum well (MQW) semiconductor optical waveguides in this research. Due to the absence of a well-defined formula for modeling the dependence of the refractive index on the quantum effects, we treat the MQW as a multilayer one with the refractive index of each thin layer taken to be that of the corresponding bulk material but with a modified anisotropic factor. When analyzing a slab MQW waveguide, numerical solutions of the effective refractive index, the birefringence, and the intensity-dependent dispersion relations are obtained. By using a truncation method to handle the infinite boundary, the scalar FEM is also utilized to study the three-dimensional ridge-loading MQW waveguides. Solution of the effective refractive index and the birefringence can be accurately obtained. We discuss the waveguide characteristics for various layered structures and wavelengths. Directional couplers consisting of two identical ridge-loading waveguides are studied and the effect of the degree of symmetry on the operation of these couplers is examined as well. Power transfer behaviors between the two waveguides including the possible polarization and wavelength beamsplitting are examined. Finally, several applications such as the optical switches and logic gates using the nonlinear material properties of the waveguide structure are discussed.