Research On Integrated Characteristics And Applications Of Photonic Crystal Waveguide

As a new type of artificial band gap electromagnetic material, photonic crystal possesses many good characteristic, such as restraining spontaneous radiation, compact size, integrated, etc. Especially for photonic crystal waveguide, it can control the flow of photonic flexibly, and is the ideal platform that realizes photonic integrated circuit, and plays an important role in optical communication and optical network. It is significant to study the photonic crystal waveguide integrated device. This thesis studied the integrated characteristics of photonic crystal waveguide and its application in optical integrated device. The main work and results are as follows:Firstly, the characteristic of photonic crystal channel drop filter achieved by integrating ring-shaped waveguide and microcavity is studied. Photonic crystal point defect and line defect are integrated to design a photonic crystal channel drop filter. The impact of structure parameters of microcavity and ring-shaped waveguide on drop channel is analyzed by simulation. A method of fine tuning resonant frequency is analyzed. The notch depth and bandwidth can get98%and0.4nm respectively. Finally, this channel drop filter can be used to60GHz radio over fiber system to filter one sideband signal of double sideband signal to achieve sideband modulation.Secondly, the characteristic of demultiplexer achieved by integrating coupled cavity waveguide are studied. A method of improving the transmission based on keeping bandwidth unchanged is simulated and analyzed, that the defect rod in micocavity is shifted along the center of waveguide structure, and the maximum normalized transmission is99.5%. Finally, four kinds of coupled waveguides were designed by applying this optimization method, and the spacing of their center wavelengths is20nm. And then these four waveguide were integrated with one photonic crystal line waveguide, and formed four channels demultiplexer. This demultiplexer satisfied the coarse wavelength division multiplexing standard of ITU-T G.694.2.Lastly, the characteristic of all optical logic gate achieved by integrating photonic crystal multimode interference waveguides is studied. Two kinds of multimode interference waveguide and self-imaging theory are analyzed, and find the position in waveguide that can produce extinction phenomenon. These two kinds of waveguide was integrated to form logic gate, and one kind of waveguide served as input and output ports, the other kind of waveguide served as multimode interference waveguide, and its size was approximately6.9μm×6.7μm. This logic gate can achieve XOR, XNOR, NAND and OR logical calculations for BPSK signals by defining input and output logical value. The extinction ratio between the ON state and the OFF state for XOR, XNOR, NAND and OR gates are more than28.6dB,28.6dB,25dB and26.6dB in the whole C-band, respectively. The conversion efficiency and transmission ratio are get98%and93%respectively. Finally, the fabrication tolerance are analyzed, and when all the rods radius in the logic models are bigger0%,-10%,10%,20%and30%than theoretical designed parameters, the ON to OFF logic level extinction ratio in the whole C-band is28.6dB,10dB,25dB,20dB and10dB, respectively.In summary, these research work and results provide novel idea to design photonic crystal waveguide integrated devices and their application, and have important guidance significance and reference value to theoretical research on photonic crystal integrated optical devices.