Gui Yaliang, Nouri Behrouz Movahhed, Miscuglio Mario, Amin Rubab, Wang Hao, Khurgin Jacob B, Dalir Hamed, Sorger Volker J
George Washington University, 800 22nd Street NW, Washington, DC 20052, USA.
Johns Hopkins University, Baltimore 21208, MD, USA.
Nanophotonics. 2022 Apr 8;11(17):4001-4009. doi: 10.1515/nanoph-2021-0796. eCollection 2022 Sep.
Electro-optic modulators provide a key function in optical transceivers and increasingly in photonic programmable application-specific integrated circuits (ASICs) for machine learning and signal processing. However, both foundry-ready silicon-based modulators and conventional material-based devices utilizing lithium-niobate fall short in simultaneously providing high chip packaging density and fast speed. Current-driven ITO-based modulators have the potential to achieve both enabled by efficient light-matter interactions. Here, we introduce micrometer-compact Mach-Zehnder interferometer (MZI)-based modulators capable of exceeding 100 GHz switching rates. Integrating ITO-thin films atop a photonic waveguide, one can achieve an efficient = 0.1 V mm, spectrally broadband, and compact MZI phase shifter. Remarkably, this allows integrating more than 3500 of these modulators within the same chip area as only one single silicon MZI modulator. The modulator design introduced here features a holistic photonic, electronic, and RF-based optimization and includes an asymmetric MZI tuning step to optimize the extinction ratio (ER)-to-insertion loss (IL) and dielectric thickness sweep to balance the trade-offs between ER and speed. Driven by CMOS compatible bias voltage levels, this device is the first to address next-generation modulator demands for processors of the machine intelligence revolution, in addition to the edge and cloud computing demands as well as optical transceivers alike.
电光调制器在光收发器中发挥着关键作用，并且在用于机器学习和信号处理的光子可编程专用集成电路（ASIC）中也越来越重要。然而，无论是可用于代工的硅基调制器，还是采用铌酸锂的传统材料基器件，都无法同时提供高芯片封装密度和高速性能。基于电流驱动的氧化铟锡（ITO）调制器有潜力通过高效的光与物质相互作用实现这两点。在此，我们介绍基于微米级紧凑型马赫曾德尔干涉仪（MZI）的调制器，其开关速率能够超过100GHz。在光子波导顶部集成ITO薄膜，可以实现效率为0.1V/mm、光谱宽带且紧凑的MZI移相器。值得注意的是，这使得在与单个硅MZI调制器相同的芯片面积内能够集成超过3500个这样的调制器。这里介绍的调制器设计具有基于光子、电子和射频的整体优化，包括一个非对称MZI调谐步骤以优化消光比（ER）与插入损耗（IL），以及介电层厚度扫描以平衡ER与速度之间的权衡。由CMOS兼容偏置电压电平驱动，该器件不仅满足了光收发器以及边缘和云计算的需求，还是首个满足机器智能革命中下一代调制器对处理器要求的器件。
