Silicon ring resonator-coupled Mach–Zehnder interferometers for the Fano resonance in the mid-IR

Abstract

We present ring resonator (RR)-coupled Mach-Zehnder interferometers (MZIs) based on silicon-on-insulator rib waveguides, operating around the mid-IR wavelength of 3.8 μm. A number of different photonic integrated devices have been designed and fabricated experimentally to obtain the asymmetric Fano resonances in the mid-IR. We have investigated the influence of the coupling efficiency between the RR and the MZI as well as the phase shift between the two arms of the MZI on the Fano-type resonance spectral features, in agreement with theoretical predictions. Finally, wavelength-dependent Fano transmittances have been successfully measured with insertion losses up to ∼1 dB and extinction ratios of ∼20 dB. A slope of sharp Fano resonances as high as -574.6/μm has been achieved and estimated to be 35.5% higher than the slope of single RR Lorentzian-type resonances.

Progress of silicon photonic devices-based Fano resonance

“…多MRR产生Fano共振方法方案及其对应的 性能指标如表3所列. 调制器的线性度 [79] , Chen等 [80] 在实验上证明此 表 3 多MRR产生Fano共振的参数表 结构可以有效地应用在硅基MZI调制器中, 另外, 该结构也可以在中红外波段3.8 µm范围实现Fano 共振 [81] , 斜率比单个MRR共振的斜率高35.5%.…”

“…最新研究表明 [80] , 在MZI的臂上加上光衰减 器用于调节双臂的功率比值(图11(a)), 可灵活调 节最佳工作点, 验证了Cardenas等 [97] 出端口的高消光比, 旨在降低开关恢复时间和功 耗 [86] ; 调制器中MRR的损耗对线性调制深度影响 较大, 同时需要优化MZI 两个臂功率比值, 旨在减 小一阶及高阶失真度 [82] ; 应用到基于强度检测的 光传感时, 目标是透射光谱的具有高的斜率. 因此, Fano共振在传感应用中参数优化具有特殊性.…”

“…11. Silicon electro-optic modulator based on Fano resonant: (a) MZI couple MRR [80] ; (b) single waveguide PCNC [98] .…”