El Shamy Raghi S, Afifi Abdelrahman E, Badr Mohamed M, Swillam Mohamed A
Department of Physics, The American University in Cairo, New Cairo, 11835, Egypt.
Electrical and Computer Engineering Department, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Sci Rep. 2022 Mar 4;12(1):3598. doi: 10.1038/s41598-022-07449-0.
This work presents a loop terminated asymmetric Mach-Zehnder interferometer (LT-aMZI) structure based on the widespread silicon-on-insulator (SOI) platform. Four different path length differences of the LT-aMZI, which correspond to free spectral ranges (FSR) from 0.8 to 6.4 nm, are designed. These designs are compared to the common asymmetric Mach-Zehnder interferometer (C-aMZI) and are shown to be more compact. These devices are suitable for optical filtering as well as wavelength demultiplexing (WDM) applications. A compact analytical model is derived that accurately describe the operation of the LT-MZI devices. The designs are then fabricated using Electron Beam Lithography (EBL) and characterized. The experimental data show good agreement when compared to the simulation results. To our knowledge, this is the first time LT-aMZI fabrication and characterization. Moreover, the LT-MZI spectrum can be tuned not only by the interferometer arms phase difference like C-MZI, but also by using its directional couplers coefficients, forming a spectral tunable filter. Finally, we determine the performance parameters of optical sensors and modulators and show that our proposed LT-MZI structure will enhance the sensor figure of merit (FOM) and modulator speed, power consumption and V × L compared to C-MZI. A comparison between symmetric and asymmetric MZI sensors and the advantage of the latter is also mentioned.
这项工作提出了一种基于广泛使用的绝缘体上硅（SOI）平台的环形端接非对称马赫-曾德尔干涉仪（LT-aMZI）结构。设计了LT-aMZI的四种不同光程差，其对应于0.8至6.4纳米的自由光谱范围（FSR）。将这些设计与普通非对称马赫-曾德尔干涉仪（C-aMZI）进行比较，结果表明其结构更为紧凑。这些器件适用于光学滤波以及波长解复用（WDM）应用。推导了一个紧凑的解析模型，该模型能准确描述LT-MZI器件的工作原理。然后使用电子束光刻（EBL）技术制造这些设计并进行表征。实验数据与模拟结果相比显示出良好的一致性。据我们所知，这是首次对LT-aMZI进行制造和表征。此外，LT-MZI的光谱不仅可以像C-MZI那样通过干涉仪臂的相位差进行调谐，还可以通过其定向耦合器系数进行调谐，从而形成一个光谱可调谐滤波器。最后，我们确定了光学传感器和调制器的性能参数，并表明与C-MZI相比，我们提出的LT-MZI结构将提高传感器的品质因数（FOM）以及调制器的速度、功耗和V×L。还提到了对称和非对称MZI传感器之间的比较以及后者的优势。
