Fast and efficient light generation and transport are at the heart of modern on-chip optical communication and information processing technologies. Next generation on-chip light sources must have a high modulation bandwidth and low energy consumption while maintaining a small footprint to be competitive. Enabled by metal-cladded nanocavities, fast subwavelength light emitters in the form of both lasers and LEDs have been analytically or experimentally demonstrated. From the modulation bandwidth perspective, nanolasers are ultimately limited by gain compression at high injection currents. From the energy efficiency perspective, nanolasers are inefficient due to the required high injection current to compensate for the losses in order to reach the lasing threshold. In contrast, nanoLEDs can simultaneously have Purcell effect enhanced speed, high energy efficiency, and output power that is above the thermal noise limit. This brief review aims to bolster, in a comparative approach, rationales of why nanoLEDs are a competitive alternative to nanolasers as light sources in chip-scale optical communication systems.

快速高效的光产生和传输是现代片上光通信和信息处理技术的核心。下一代片上光源必须具有高调制带宽和低能耗，同时保持小尺寸才能具有竞争力。通过金属包覆的纳米腔，激光器和 LED 形式的快速亚波长光发射器已被分析或实验证明。从调制带宽的角度来看，纳米激光器最终受到高注入电流下增益压缩的限制。从能效的角度来看，纳米激光器效率低下，因为需要高注入电流来补偿损耗才能达到激光阈值。相比之下，nanoLED 可以同时具有珀塞尔效应增强的速度，高能效，输出功率高于热噪声极限。这篇简短的评论旨在通过比较方法来支持为什么纳米 LED 是纳米激光器作为芯片级光通信系统中光源的竞争替代品的基本原理。