Direct-detection (DD) Stokes vector receiver (SVR) has rapidly gained interest for the high-speed datacenter and short-reach links, owing to its capability of recovering 3D optical signals without using expensive coherent detection. In order to reduce the size and cost of SVR, we have recently proposed and demonstrated a simple and compact device with single-ended photodetectors (S-PDs), which can be monolithically integrated on InP. In this paper, we provide comprehensive analysis on the receiver sensitivity for different SVR configurations. From rigorous theoretical investigations, we derive optimal design of SVR to maximize the sensitivity as well as explicit analytical expression of the bit-error-rate assuming an unamplified thermal-noise-limited case. From the obtained results, we find that the optimized 4-port S-PD-based SVR exhibits a moderate penalty of 2.1 dB with respect to the conventional more complicated SVR configuration based on 3-port balanced PDs. Since the proposed S-PD-based SVR can reduce the number of PDs, and requires neither a polarization-beam splitter nor precisely tuned optical interferometer, it may be an attractive candidate in realizing a low-cost and compact fully integrated DD-based receiver for the future >Tb/s short-reach systems, where the power budget is not the primary concern.

中文翻译：

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光子集成直接检测斯托克斯矢量接收器的灵敏度分析

直接检测 (DD) 斯托克斯矢量接收器 (SVR) 因其无需使用昂贵的相干检测即可恢复 3D 光信号的能力而迅速引起了对高速数据中心和短距离链路的关注。为了减小 SVR 的尺寸和成本，我们最近提出并展示了一种带有单端光电探测器 (S-PD) 的简单紧凑的器件，它可以单片集成在 InP 上。在本文中，我们对不同 SVR 配置的接收器灵敏度进行了全面分析。从严格的理论研究中，我们推导出 SVR 的优化设计，以最大化灵敏度以及假设未放大的热噪声限制情况下误码率的显式分析表达式。从得到的结果来看，我们发现优化的基于 4 端口 S-PD 的 SVR 相对于基于 3 端口平衡 PD 的传统更复杂的 SVR 配置表现出 2.1 dB 的适度损失。由于所提出的基于 S-PD 的 SVR 可以减少 PD 的数量，并且既不需要偏振分束器也不需要精确调谐的光学干涉仪，它可能是实现低成本和紧凑的完全集成的基于 DD 的接收器的有吸引力的候选者对于未来 >Tb/s 的短距离系统，功率预算不是主要问题。