Electro-optic modulators are utilized ubiquitously ranging from applications in data communication to photonic neural networks. While tremendous progress has been made over the years, efficient phase-shifting modulators are challenged with fundamental tradeoffs, such as voltage-length, index change-losses or energy-bandwidth, and no single solution available checks all boxes. While voltage-driven phase modulators, such as based on lithium niobate, offer low loss and high speed operation, their footprint of 10’s of cm-scale is prohibitively large, especially for density-critical applications, for example in photonic neural networks. Ignoring modulators for quantum applications, where insertion loss is critical, in this work we distinguish between current versus voltage-driven modulators. We focus on the former, since current-based schemes of emerging thin electro-optical materials have shown unity-strong index modulation suitable for heterogeneous integration into foundry waveguides. Here, we provide an in-depth ab-initio analysis of obtainable modulator performance based on heterogeneously integrating low-dimensional materials, i.e., graphene, thin films of indium tin oxide, and transition metal dichalcogenide monolayers into a plurality of optical waveguide designs atop silicon photonics. Using the fundamental modulator tradeoff of energy-bandwidth-product as a design-quality quantifier, we show that a small modal cross section, such as given by plasmonic modes, enables high-performance operation, physically realized by arguments on charge-distribution and low electrical resistance. An in-depth design understanding of phase-modulator performance, beyond doped-junctions in silicon, offers opportunities for micrometer-compact yet energy-bandwidth-ratio constrained modulators with timely opportunities to hardware-accelerate applications beyond data communication towards photonic machine intelligence, for instance; where both performance and integration-density are critical.

中文翻译：

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基于新兴材料的集成电光相位调制器的性能分析

电光调制器被广泛使用，从数据通信应用到光子神经网络。虽然这些年来取得了巨大的进步，但高效的相移调制器面临着基本权衡的挑战，例如电压长度、指数变化损失或能量带宽，并且没有可用的单一解决方案来满足所有条件。虽然电压驱动的相位调制器，例如基于铌酸锂的，提供低损耗和高速运行，但它们的 10 厘米尺度的足迹非常大，特别是对于密度关键的应用，例如在光子神经网络中。忽略插入损耗至关重要的量子应用调制器，在这项工作中，我们区分了电流驱动调制器和电压驱动调制器。我们专注于前者，由于新兴薄电光材料的基于电流的方案已显示出适用于异质集成到代工波导中的强单位指数调制。在这里，我们基于将低维材料（即石墨烯、氧化铟锡薄膜和过渡金属二硫属化物单层）异质集成到硅顶上的多个光波导设计中，对可获得的调制器性能进行了深入的从头分析光子学。使用能量带宽积的基本调制器权衡作为设计质量量词，我们表明小的模态横截面，例如由等离子体模式给出的，能够实现高性能操作，通过关于电荷分布和低电阻。对相位调制器性能的深入设计理解，例如，除了硅中的掺杂结之外，还为微米级紧凑但能量带宽比受限的调制器提供了机会，并及时为硬件加速应用程序提供了超越数据通信到光子机器智能的机会；其中性能和集成密度都至关重要。