复合结构光子晶体耦合腔波导慢光特性研究

Investigation on slow light in composite-structure photonic crystal coupled-cavity waveguide

为了设计能够传输宽带低色散慢光的光子晶体波导,以三角晶格圆形介质柱光子晶体结构为基础,使用圆形散射元和椭圆形散射元进行周期性排列,采用平面波展开法对所设计的耦合腔波导进行了仿真分析。结果表明,调整缺陷行椭圆形散射元长轴R_a可以使导模最大群速度从0.035c降低到0.01c,调节缺陷行短轴R_b的值,可以再次降低导模群速度;通过改变微腔周围第1排两种散射元的面积比,能够得到最大群速度0.0065c,波长范围为3.25nm的低色散慢光;将所设计的耦合腔应用于光缓存中,计算得出缓存时间为76.82ps,存储容量达到了15.56bit。这项研究对新型光子晶体慢光器件的设计和应用具有参考意义。

In order to design a photonic crystal waveguide which can propagate slow light with wide band and low dispersion,on the basis of photonic crystal structure of triangular lattice dielectric cylinder,the periodic arrangement was carried out using circular scatterers and elliptic scatterers. Plane wave expansion method was used to simulate the designed coupled cavity waveguide. The results show that the maximum group velocity of guided mode decreases from 0. 035 c to 0. 01 c by changing long axis Raof oval scatterers in defect line. The group velocity can be further decreased when short axis Rbin defect line is changed.Further study shows that by changing area ratio of two scatterers of the first row around the microcavity,the maximum group velocity is reduced to 0. 0065 c,and low dispersion slow light with wavelength range of 3. 25 nm was gotten. When the designed coupled cavity was used in optical buffer,cache time of 76. 82 ps and the maximum ache capacity of 15. 56 bit can be achieved.The research has reference value in the design and application of novel devices based on photonic crystal waveguides.