The Design And Analysis Of Multi-channel Filter Based On Defect Photonic Ctystal

With the rapid development of the biological sensing technology, photonic crystal biosensor, the centre of biological sensing system, not only had small size, but also could manufacture with other variety of optical devices in the same one piece of substrate, so that the cost of sensing detection system could be reduced. The centre of photonic crystal biosensors was a chip made of photonic crystal filter structure. Researching and improving the filtering performance was the basis of its application, and multi-channel photonic crystal filter had a major role in detecting the determinand of biological sensing system. This article mainly studied how to get a better filtering effect with the multi-channel photonic crystal filter. The main work of this article was:On the basis of electromagnetic field theory, the basic analytical method of photonic crystals has been researched, and the design principle and performance index of the multi-channel photonic crystal filter has been analyzed by using simulation software. In view of the photonic crystal resonant cavity, waveguide and ring cavity, the plane wave expansion method has been used to analyze the band characteristic of the three kinds of defect. The finite difference time domain method has been used to analyze the output characteristics of the three kinds of defect, and the influence of dielectric cylinder radius and refractive index to the output spectrum of single-channel photonic crystal filter were also be analyzed. All the research laid a solid foundation for further study on multi-channel photonic crystal filter.A new-type combined filter structure based on three kinds of defect photonic crystals has been put forward. First, the single-channel filter of combination structure has been studied, and the influence of refractive index and radius to the output spectrum of single-channel photonic crystal filter were also be analyzed; A dual-channel filter structure was given based on the single-channel filter, using this new filter could achieve dual-channel filtering at the same time, and the influence of refractive index to the output spectrum were also be discussed. According to the conclusion, both structures could get a good filtering effect by adjusting the refractive index of the point defect dielectric. These rules could be extended to the combination multi-channel filter structure, then the multi-channel filter based on photonic crystal ring cavity could be used to test the material of biological sensing system.