All-silicon (Si) photodiodes have drawn significant interest due to their single and simple material system and perfect compatibility with complementary metal-oxide semiconductor photonics. With the help from a cavity enhancement effect, many of these photodiodes have shown considerably high responsivity at telecommunication wavelengths such as 1310 nm, yet the mechanisms for such high responsivity remain unexplained. In this work, an all-Si microring is studied systematically as a photodiode to unfold the various absorption mechanisms. At -6.4V, the microring exhibits responsivity up to ∼0.53A/W with avalanche gain, a 3 dB bandwidth of ∼25.5GHz, and open-eye diagrams up to 100 Gb/s. The measured results reveal the hybrid absorption mechanisms inside the device. A comprehensive model is reported to describe its working principle, which can guide future designs and make the all-Si microring photodiode a promising building block in Si photonics.

Silicon photonics technology has drawn significant interest due to its potential for compact and high-performance photonic integrated circuits. The Ge- or III–V material-based avalanche photodiodes integrated on silicon photonics provide ideal high sensitivity optical receivers for telecommunication wavelengths. Herein, the last advances of monolithic and heterogeneous avalanche photodiodes on silicon are reviewed, including different device structures and semiconductor systems.

高温气冷堆是国际公认的固有安全性高的反应堆堆型。针对高温气冷堆包覆颗粒燃料引入的燃料组件的双重非均匀性以及棱柱式堆芯布置的非均匀性和强空间耦合效应，提出基于蒙特卡罗均匀化-确定论输运方法的RMC-SaraGR程序系统作为棱柱式高温气冷堆的核设计程序。基于日本棱柱式高温气冷堆临界实验装置VHTRC基准题，针对此套核设计程序系统开展了均匀化模型研究和初步验证。研究结果表明，基于蒙特卡罗均匀化方法，采用全堆模型、合适的能群结构和分区方式产生组件群常数，并经过超级等效均匀化方法进行等效均匀化修正，可以保证堆芯多群均匀计算具有较高的计算精度。