Fard Monireh Moayedi Pour, Cowan Glenn, Liboiron-Ladouceur Odile
Opt Express. 2016 Nov 28;24(24):27738-27752. doi: 10.1364/OE.24.027738.
This paper experimentally demonstrates a design optimization of an evanescently-coupled waveguide germanium-on-silicon photodetector (PD) towards high-speed (> 30 Gb/s) applications. The resulting PD provides a responsivity of 1.09 A/W at 1550 nm, a dark current of 3.5 µA and bandwidth of 42.5 GHz at 2 V reverse-bias voltage. To optimize the PD, the impact of various design parameters on performance is investigated. A novel optimization methodology for the PD's responsivity based on the required bandwidth is developed. The responsivity of the PD is enhanced by enlarging its geometry and using off-centered contacts on top of the germanium, while an integrated peaking inductor mitigates the inherent bandwidth reduction from the responsivity optimization. The performance of the optimized PD and the conventional, smaller size non-optimized PD is compared to validate the optimization methodology. The sensitivity of the optimized PD improves by 3.2 dB over a smaller size non-optimized PD. The paper further discusses the impact of top metal contacts on the photodetector's performance.
本文通过实验展示了一种用于高速（> 30 Gb/s）应用的倏逝耦合波导硅基锗光电探测器（PD）的设计优化。所得到的光电探测器在1550 nm波长处的响应度为1.09 A/W，暗电流为3.5 μA，在2 V反向偏置电压下的带宽为42.5 GHz。为了优化该光电探测器，研究了各种设计参数对其性能的影响。基于所需带宽开发了一种用于光电探测器响应度的新型优化方法。通过扩大其几何尺寸并在锗顶部使用偏心接触来提高光电探测器的响应度，同时集成的峰值电感减轻了响应度优化带来的固有带宽降低。比较了优化后的光电探测器和传统的、较小尺寸的非优化光电探测器的性能，以验证优化方法。优化后的光电探测器的灵敏度比小尺寸非优化光电探测器提高了3.2 dB。本文还讨论了顶部金属接触对光电探测器性能的影响。
