二维光子晶体多通道滤波器的设计

发布时间：2018-05-19 12:03

本文选题：光子晶体 + 滤波器　；参考：《华中科技大学》2015年硕士论文

【摘要】：不同介电常数的材料在空间中周期性排列形成的光子晶体,具有光子禁带和光子局域两大主要特性。利用这些特性,在光子晶体结构中引入点/线缺陷,能够制作出易于大规模集成的高性能、低损耗和微尺寸的光学器件。本文研究了波导、微腔和环形谐振腔等基本结构,并结合几种结构的耦合特性,设计和优化了多通道光子晶体滤波器。首先,研究光子晶体波导的结构特性,利用平行波导实现光波的耦合,并结合耦合长度对不同光波具有选择性等特点,设计了三通道平行波导滤波器。在此基础上,增加入射端介质柱密度降低光波反射,调节耦合介质柱半径降低光波散射,从而进一步提高滤波器工作效率。优化之后,1310nm、1490nm和1550nm透射率分别是82.4%、91.2%和76.6%。这种方式设计的三通道滤波器结构简单,尺寸为400.5μm2,但是各通道间串扰比较大,造成1550nm波长的透射率只有76.6%。其次,研究了光子晶体微腔的结构特性,利用微腔和波导实现光波的耦合,并结合微腔谐振波长带宽窄等特性,设计了三通道微腔滤波器,1400nm、1490nm和1550nm透射率分别是88.9%、90.8%和82.2%。微腔耦合方式设计的三通道滤波器尺寸为153.8μm2,传输效率也比平行波导耦合方式高,设计方式更灵活,但是随着微腔数目的增加,增大了各通道间的串扰,也造成单通道透射率降低,不利于多通道之间的大规模集成。最后,分析了环形谐振腔的结构特点,利用其与波导实现光波耦合,并结合其多模特性以及谐振波长带宽窄的特点,设计的三通道环形谐振腔滤波器,透射率全部达到96%以上,尺寸为270.6μm2;在此基础上增加到五通道滤波器,信道间距为8nm,透射率也全部在92%以上,尺寸只增加了65.3μm2。环形谐振腔耦合方式设计的多通道滤波器效率高、尺寸较小、易于扩展,同时还能减小平行波导耦合和微腔耦合由于通道个数增加带来的串扰增加,可调谐性好。
[Abstract]:Photonic crystals with different dielectric constants arranged periodically in space have two main properties: photonic bandgap and photonic localization. By using these characteristics, point / line defects are introduced into the photonic crystal structure, which can be used to fabricate high performance, low loss and micro size optical devices which are easy to be integrated on a large scale. In this paper, the basic structures of waveguide, microcavity and ring resonator are studied, and the multi-channel photonic crystal filter is designed and optimized by combining the coupling characteristics of several structures. Firstly, the structure characteristics of photonic crystal waveguide are studied. The parallel waveguide is used to realize the optical wave coupling, and a three-channel parallel waveguide filter is designed in combination with the selectivity of coupling length to different light waves. On this basis, increasing the density of the dielectric cylinder at the incident end to reduce the reflection of the optical wave, adjusting the radius of the coupled dielectric cylinder to reduce the scattering of the light wave, thus further improving the efficiency of the filter. After optimization, the transmittance of 1310nm and 1550nm are 91.2% and 76.6%, respectively. The structure of the three-channel filter designed in this way is simple and the size is 400.5 渭 m ~ 2, but the crosstalk between the channels is relatively large, resulting in the transmittance of the 1550nm wavelength is only 76.66.00 渭 m ~ (2). Secondly, the structure characteristics of photonic crystal microcavity are studied. The coupling of optical wave is realized by using microcavity and waveguide, and combining with the characteristics of resonator wavelength band width, a three-channel microcavity filter is designed. The transmittance of three-channel microcavity filter is 88.9% and 82.2%, respectively, at 1490nm and 82.2nm respectively. The size of the three-channel filter is 153.8 渭 m ~ 2, the transmission efficiency is higher than the parallel waveguide coupling mode, and the design is more flexible. However, with the increase of the number of microcavities, the crosstalk between the channels is increased. It also leads to the decrease of single channel transmittance, which is not conducive to large-scale integration between multiple channels. Finally, the structural characteristics of the ring resonator are analyzed, and the optical wave coupling is realized by using the waveguide. Combined with its multi-mode characteristics and the characteristics of narrow resonant wavelength band, the three-channel ring resonator filter is designed, and the transmittance of the filter is above 96%. The size of the filter is 270.6 渭 m ~ (2), and the channel spacing is 8nm, the transmittance is above 92%, and the size is only 65.3 渭 m ~ (2). The multi-channel filter designed by the coupling mode of ring resonator is of high efficiency, small size and easy to expand. It can also reduce the crosstalk caused by the increase of the number of channels and the tunability of the parallel waveguide coupling and microcavity coupling.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN713

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