类Sagnac干涉仪结构的三维多微环谐振滤波器

Three-Dimensional Multi-Microring Resonance Filter Based on Sagnac-Like Interferometer

Sagnac干涉仪在光学滤波领域有着重要应用。基于三维氮化硅波导平台,利用双层的多微环系统实现了新型类Sagnac谐振滤波系统,其中底层主微环腔分别与顶层输入/输出波导和单/双子微环实现了反馈耦合。光经耦合区域产生了两束相向传输并互相干涉的光波,从而实现了滤波波形和谐振峰位可调的滤波结构。基于传输矩阵和迭代方法分析输出光谱,通过改变波导与微腔的耦合系数设计输出光谱波形,利用金属加热电极调制主微腔的相位以调控谐振峰位。理论分析和实验表征结果表明,通过增加顶层子微环数可有效增强器件的密集滤波效果,此三维集成结构可提供更多的设计自由度。相关的多微环谐振滤波系统可以广泛应用于光通信和光传感等领域。

Sagnac interferometers have important applications in the field of optical filtering.Based on the 3D silicon nitride waveguide platform,we obtained a new Sagnac-like resonance filter system by using a two-layer multi-microring system.In the new system,the bottom main microring cavity was coupled via feedback with the top input/output waveguide and the single/double sub-microrings,respectively.Furthermore,two light waves transmitting in the opposite direction were generated in the coupling area and interfered with each other,thereby a filter structure with adjustable filtering waveforms and resonance peak positions is realized.In this paper,a transmission matrix and an iteration method were used to analyze the output spectra,and the output waveform was designed by changing the coupling coefficient between the waveguide and the microcavity.Besides,the phase of the main microcavity was modulated by the metal heating electrode to regulate the resonance peak position.The theoretical analysis and experimental characterization results show that the dense filtering effect of the device can be effectively improved by adding top sub-microrings and thus the 3D integrated structure can provide greater design freedom.The related multi-microring resonance filter system can be widely used in optical communication,optical sensing,and other fields.