Beam Propagation Method Simulation Of Magneto-optical Materials, Optical Waveguides

With the development of integrated optical waveguide technology, all kinds of optical waveguide devices with different functions and structures have appeared. Magneto-optical waveguide devices based on magneto-optical effect, such as magneto-optical switch, optical isolator, have been more and more used in optical fiber communication and other related fields. Designing and simulating waveguide with computer numerical analysis method can not only show the characters of optical waveguide completely and reach the expectation precisely and quickly, but also reduce experiment time and investment. In this thesis, a Beam Propagation Method has been used to simulate the characters of optical waveguide based on magneto-optical material and propose a new method to resolve the mode coupled problem in magneto-optical waveguide.First, the development of integrated optics and current situation in magneto-optical waveguide in the world have been introduced, including material and theory research. Then the development of Beam Propagation Method (BPM) has been introduced. The basic calculate method of BPM, the process of boundary condition and the dispose of tridiagonal matrix have been illustrated at the same time.The emphasis of this paper is that three-dimension full-vectorial coupling equations have been derived from Maxwell's equations. The unconditional stable Crank-Nicholson difference scheme has been used to discretize the equations and assure the stability of numerical calculation. The Alternating Direction Implicit (ADI) method and the Transparent Boundary Condition (TBC) method have also been adopted and improved to increase the calculation efficiency and make the discretization more stable. Then the 3D full-vectorial Finite Difference Beam Propagation Method (FDBPM) algorithm and semi-vectorial FDBPM algorithm are got.The magneto-optical mode conversion waveguide and optical switch waveguide for different requirements are simulated separately. The simulation of magneto-optical mode conversion waveguide is based on semi-vectorial FDBPM algorithm. The TE mode and TM mode have about above 99% power exchanged while light propagates approximately 6800um. The simulation results are in excellent agreement with the theory and the stability has been fully proved. The simulation of optical switch is based on full-vectorial FDBPM algorithm. The light's power and phase change in waveguide have been both simulated while the switch is in"on"and"off"states. The results are also in good agreement with the theory and the algorithm can perfectly resolve the mode coupled problem in complicated waveguide.The innovation of this paper is that a new method to resolve the mode coupled problem in complicated magneto-optical waveguide has been presented. The method has some improvement to the traditional FDBPM, so it can perfectly resolve the three-dimension mode coupled problem. The precision, stability and efficiency in calculation are fully agreement with expectation.