Theory Research Of Photonic Crystal Applications

In this thesis, we focus on the theoretical research of photonic crystal applications with the cut-in point of fundamental design of photonic crystal function devices. Our research mainly includes the following four correlative contents:(1) Developing the platform for design and simulation. Photonic crystals are complex structures, which make it difficult to solve the photonic band structure or transmission property by analytical method. In order to deal with the theoretical research, we must develop a comprehensive platform as the numeric tool for photonic crystal design and simulation. However, the computation of 3D model requires very large memories and is time consuming, so high performance parallel computation is necessary.(2) Fundamental design of functional devices. The research mainly includes these aspects: Design of photonic crystal wavelength demultiplexers by analogy with conventional waveguide wavelength demultiplexers. Optimization for the operation mode in electrically driven single-cell photonic crystal laser cavity demonstrated by Y.H.Lee research group. Presenting a new principle of photonic crystal waveguide cavity. Presenting a new light-by-light photonic crystal switching. Development of FDTD method for analyzing the photonic crystals in the non-inertial frame for photonic crystal ring cavity.(3) Research of coupling technique. The size of photonic crystal devices is scaled down to the sub-micro-range, which is far smaller than conventional optical devices. For an integrated optical system, the coupling into and out of the photonic crystal devices would be one of key techniques.(4) Analysis of fabrication errors. In order to fabricate the photonic crystals that operate in the near-infrared or optical-wavelength, the feature size of photonic crystal has to be some hundreds of nanometers. Fabrication of such fine structures inevitably generates random deviations from the perfectly ordered structures. The effects of disorder on the performance of photonic crystal devices are also in the scope of this paper.The main research results of this paper are as follows.(1) We developed a two-dimensional photonic crystal simulation software written in Visual C++ based on FDTD method. This software which provides a modern graphical user interface can conveniently build all kinds of complex photonic crystal structures including nonlinearity, metal, dot and line defects. With the high-performance cluster systems consisting of personal computers, we also developed a parallelized three-dimensional photonic crystal FDTD code written in Message Passing Interface (MPI) and Fortran. (2) We designed two kinds of photonic crystal wavelength demultiplexers based on an analogy of conventional waveguide directional coupling and multimode interference effect.(3) We presnted a new principle of light-by-light operation based on the nonlinear optical effect difference between different positions of standing waves. We show that such a photonic crystal configuration operating on the principle can demonstrate light-by-light and all-optical AND gate operation with a wide bandwidth and high contrast between the OFF state and the ON state in its transmission.(4) We optimized the electrically driven single-cell photonic crystal laser cavity demonstrated by Y.H.Lee research group to increase the quality factor and Purcell factor of the operation mode. We show that the quality factor and Purcell factor for the modified cavity are about 7 and 6.8 times higher than that of the unmodified structure, respectively.(5) We present a new principle of photonic crystal waveguide cavity based on mode control, which utilize two narrow waveguide operating only in the Oth order mode to confine 1st order mode of wide waveguide.(6) We made tentative research on rotation effect in ring-shaped photonic crystal cavity and developed an FDTD method for simulating the photonic crystals in the non-inertial frame.(7) We present a new approach for high efficient coupling between conventional dielectric waveguide and photonic crystal waveguide by introducing a cascade tapered waveguide. The tapered waveguide is formed by increasing radii of air holes step by step.(8) We proposed a novel photonic crystal configuration consisting of coupled cavities and diffraction gratings at the photonic crystal surface to obtain beaming of light and enhanced transmission. We showed that such a configuration can demonstrate beaming of light in a wide bandwidth range and narrow radiation angle.(9) We study and discuss how do the random errors, including radius and position errors which may arise during fabrication, affect the fundamental properties of photonic crystals and the performance of photonic crystal function devices.In summary, we begin the research field of photonic crystal applications by developing the platform for design and simulation. Then, we utilize the platform to simulate the function devices based on some new principles and ideas. Finally, we study the effects of random error which inevitably arise during fabrication on the performance of the functional devices.