二维光子晶体新型四通道滤波器设计

Design of a new four-channel filter based on a two dimensional photonic crystal

摘要:

为实现光学信息的高效处理和光学器件的高度集成,根据光子晶体(photonic crystal,PC) 环形腔与波导之间的共振耦合原理,本文设计了一个基于二维三角晶格光子晶体的由点缺陷谐振腔、三角形环形谐振腔与线缺陷波导和反射异质结组成的新型四通道滤波器。利用平面波展开法(plane wave expansion method,PWEM) 得到了完整光子晶体及线缺陷波导的能带图,计算得到反射异质结对提高滤波效率有明显的作用。利用时域有限差分法(finite-difference time-domain,FDTD) ,对该四通道滤波器在1.456 μm、1.493 μm、1.422 μm、1.476 μm波长处的滤波效率进行仿真。仿真结果表明:通过调节谐振腔中心介质柱半径等参数,该四通道滤波器的滤波效率均在99.84%以上,实现了高效率的滤波输出。此外,滤波器各信道的最大插入损耗仅为0.009 dB,半峰宽小于7.2 nm,品质因数大于207。本文设计的四通道滤波器实现了窄带滤波且性能参数良好,在光通信应用中具有较好的适用性和可推广性。

Abstract:

In order to realize the efficient processing of optical information and the high integration of optical devices,according to the principle of resonant coupling between the ring cavity and the waveguide of a photonic crystal (PC),in this paper,we design a novel four-channel filter consisting of a point-defect resonator,a triangular ring resonator and a line defect waveguide and a reflective heterojunction based on a two-dimensional triangular lattice photonic crystal.The band maps of intact photonic crystals and line defect waveguides are obtained by plane wave expansion method (PWEM).The calculated results show that the reflected heterojunction has obvious effect on improving the filtering efficiency.Using the finite-difference time-domain method (FDTD),the filtering efficiency of the four-channel filter at 1.456 μm,1.493 μm,1.422 μm and 1.476 μm is simulated.The simulation results show that the filtering efficiency of the four-channel filter is above 99.84%,realizing the high efficiency filter output by adjusting parameters,such as the center medium column radius of the resonator .Moreover,the maximum insertion loss of each channel of the filter is only 0.009 dB,full width at half maximum less than 7.2 nm,and quality factor greater than 207.The four-channel filter designed in this paper achieves narrowband filtering and good performance parameters,with good applicability and generalizability in optical communication applications.