为设计性能优异的大调谐带宽的滤波器,在二维光子晶体结构中,利用波导与微型谐振器不同耦合结构设计了带有两类微型谐振腔的4种滤波器,借助于耦合模理论(CMT)定性分析了相位失谐因子、耦合因子比值改变对滤波器工作性能产生的影响。调节5×5微型谐振器的柱半径大小,用时域有限差分法(FDTD)方法研究了滤波器传输谱特性,结果表明:3种对称结构提取的各个峰值波长具有归一化传输率高(85.3%~99.9%)、通带宽度窄(1.8~5.6 nm)、提取峰值波长调谐范围宽(1308.0~1582.3 nm)的特性。与非对称结构滤波器相比较,对称结构滤波器的提取峰值波长具有更高的归一化传输率,其结构在光学信号提取接口、光传感、光互联网络设计上有潜在的利用价值。

In order to design a wideband bandwidth-tunable filter, we design four kinds of filters with two types of micro cavities through different coupling structures between the waveguide and the micro resonator in the two-dimensional photonic crystal structure. By means of the coupled mode theory (CMT), we qualitatively analyze the influences of phase detuning factor and ratio of coupling quality factors on the fiber performances. We use finite-difference time-domain (FDTD) method to study the transmission spectra of the filter by adjusting rod radii of the 5×5 micro resonators. The simulated results show that the three symmetrical filters have high normalized transmission (85.3%-99.9%), narrow bandwidth (1.8-5.6 nm), and broad tunable range for extracting peak wavelength (1308.0-1582.3 nm) at each peak wavelength. Compared with the asymmetrical filter, symmetrical filters have higher normalized transmission at peak wavelength. The symmetrical structures have potential value in the designs of optical signal extraction interfaces, optical sensing, and optical interconnection networks.