Germanium/silicon (Ge/Si) avalanche photodiode (APD) has emerged as a highly desirable component for optical communication, sensing, and computing, attributed to its inherent gain. Conventional schemes typically suffer from limited bandwidth and significant excess noise due to the high gain, restricting the high‐sensitivity detection in burgeoning high‐speed applications. Here, a Ge/Si APD is developed with an ultra‐large bandwidth at an optimal gain. This breakthrough is achieved by implementing an extremely narrow multiplication layer to enhance the space charge effect, overcoming the intrinsic bandwidth limitation in conventional APDs while elaborately harnessing the gain to a moderate value to ensure the optimal sensitivity. The device possesses a bandwidth of 67 GHz at an optimal gain of 6.6 and enables data reception of 240 Gb s−1 four‐level pulse amplitude modulation signal—the largest bandwidth and highest single‐channel bitrate among all reported APDs. The presented APD suggests promising applications for high‐speed and high‐sensitivity data communication owing to its competitive performance, cost‐effectiveness, and high‐yield production.

中文翻译：

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超大带宽和超高灵敏度锗/硅雪崩光电二极管


锗/硅 （Ge/Si） 雪崩光电二极管 （APD） 由于其固有的增益，已成为光通信、传感和计算中非常理想的元件。由于高增益，传统方案通常带宽有限且噪声过大，从而限制了新兴高速应用中的高灵敏度检测。在这里，开发了具有超大带宽和最佳增益的 Ge/Si APD。这一突破是通过实现极窄的乘法层来增强空间电荷效应，克服了传统 APD 的固有带宽限制，同时精心利用增益到适中值以确保最佳灵敏度。该器件具有 67 GHz 的带宽和 6.6 的最佳增益，并支持 240 Gb s−1 四电平脉冲幅度调制信号的数据接收，这是所有已报道的 APD 中带宽最大、单通道比特率最高的。所提出的 APD 由于其具有竞争力的性能、成本效益和高产量生产，为高速和高灵敏度数据通信提出了有前途的应用。