The purpose of this paper is twofold. First, we discuss the efficiency-speed tradeoff in slow-light (SL) silicon photonic (SiP) modulators. For this, a comprehensive model for the electro-optic (EO) response of lumped-electrode SL Mach-Zehnder modulators (SL-MZMs) is presented. The model accuracy is verified by comparing it to experiments. Our analysis shows that slowing down the optical wave helps to enhance efficiency by increasing the interaction time between the optical wave and the uniform voltage across lumped electrodes, but at the cost of limiting the EO bandwidth. Then, we investigate SL-MZMs with traveling-wave (TW) electrodes whose dynamic interaction is predicted using a distributed circuit model. Having been solved by the finite-difference time-domain (FDTD) method, the model shows that TW SL-MZMs are capable of improving both efficiency and speed under an optimized SL effect. We also compare SL-MZMs with conventional MZMs (C-MZM) considering a figure of merit (FOM) that combines key parameters such as efficiency, loss, and EO bandwidth. We show that the additional loss of SL waveguides significantly impacts the preferred modulator choice at different baudrates. The second aim of this paper is to examine different design strategies to reduce Vπ of C-MZMs in order to meet the requirement of COMS driver using 1) a longer phase shifter, 2) higher doping densities, and 3) the SL effect. It is shown that the SL effect provides the best overall performance among the three. Indeed, only the SL effect offers simultaneous improvement in Vπ, footprint, and EO bandwidth; the other approaches provide Vπ reduction but at the cost of reduced speed or enlarged footprint (or even both).

中文翻译：

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慢光硅光子调制器的效率-速度权衡

本文的目的是双重的。首先，我们讨论慢光 (SL) 硅光子 (SiP) 调制器的效率-速度权衡。为此，提出了集总电极 SL Mach-Zehnder 调制器 (SL-MZM) 的电光 (EO) 响应的综合模型。通过与实验进行比较来验证模型的准确性。我们的分析表明，通过增加光波与集总电极上的均匀电压之间的相互作用时间，减慢光波有助于提高效率，但代价是限制了 EO 带宽。然后，我们研究了带有行波 (TW) 电极的 SL-MZM，其动态相互作用使用分布式电路模型进行预测。已通过有限差分时域 (FDTD) 方法求解，该模型表明，TW SL-MZM 能够在优化的 SL 效应下提高效率和速度。我们还考虑了结合了效率、损耗和 EO 带宽等关键参数的品质因数 (FOM)，将 SL-MZM 与传统 MZM (C-MZM) 进行了比较。我们表明，SL 波导的额外损耗会显着影响不同波特率下的首选调制器选择。本文的第二个目的是研究降低 C-MZM 的 Vπ 的不同设计策略，以满足 COMS 驱动器使用 1) 更长的移相器、2) 更高的掺杂密度和 3) SL 效应的要求。结果表明，SL 效应在三者中提供了最佳的整体性能。实际上，只有 SL 效应可以同时改善 Vπ、占用空间和 EO 带宽；