Research On Transmission Characteristics Of Planar Optical Waveguide With Arbitrary Refractive Index Distribution

As the basic components of integrated optics, the planar waveguide is widely used in optical amplifiers, optical sensors and other optical devices. Technologies develop fast, leading to optical waveguide devices more diverse in design and manufacturing techniques. It can’t afford to do so complex devices with Maxwell equations subjected to the appropriate boundary conditions. However, numerical methods currently used seldom work very well in both less computation and higher speed. So a new method, compared with ATMM used as match and supplement, is put forward to thoroughly analyze effects of planar waveguides with different refractive index profiles on its double refraction, group velocity dispersion, and power constraint factor.In the beginning, the paper discusses shortcomings of several numerical methods commonly used nowadays, and then introduces the thesis of space-frequency domain iterative method; the key of the method is to solve convolution integral with high efficiency. The FFTW algorithm for Fourier transforms is testified with high processing capability, and it can ensure the time and accuracy of the method. The paper gives examples of three-layer with step index profiles and the other with parabolic. Computed them by Space-frequency domain iterative method, compare the calculation results with the theory’s in order to test and verify errors.And second, the ATMM is focused on. Based on real matrix constructed with particular solution of wave equation, the ATMM has a clear physical meaning without complex arithmetic. Achieving it with C language can draw dispersion curves of every mode, and then verify the accuracy.Finally, as to several typical graded index distributions, analyze the characteristics with space-frequency domain iterative method for solving the field distribution and the ATMM for dispersion curves. After repeated comparison, we discuss that the area of the refractive index distribution curve and its difference between the core and the cladding layer, play an important role in the three characteristics. In addition, paper also studies the characteristics of symmetric five-layer waveguide in constraints of electromagnetic fields, and discusses the group velocity dispersion of W type profile, as well as field intensity o of concavity type profile.