Generating optical combs in a small form factor is of utmost importance for a wide range of applications such as datacom, LIDAR, and spectroscopy. Electrically powered mode-locked diode lasers provide combs with a high conversion efficiency, while simultaneously allowing for a dense spectrum of lines. In recent years, a number of integrated chip scale mode-locked lasers have been demonstrated. However, thus far these devices suffer from significant linear and nonlinear losses in the passive cavity, limiting the attainable cavity size and noise performance, eventually inhibiting their application scope. Here, we leverage the ultra-low losses of silicon-nitride waveguides to demonstrate a heterogeneously integrated III-V-on-silicon-nitride passively mode-locked laser with a narrow 755 MHz line spacing, a radio frequency linewidth of 1 Hz and an optical linewidth below 200 kHz. Moreover, these comb sources are fabricated with wafer scale technology, hence enabling low-cost and high volume manufacturable devices.

中文翻译：

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低噪声非均相 III-V 氮化硅锁模梳状激光器

以小尺寸生成光梳对于数据通信、激光雷达和光谱等广泛的应用至关重要。电动锁模二极管激光器提供具有高转换效率的梳子，同时允许密集的谱线。近年来，已经展示了许多集成芯片级锁模激光器。然而，到目前为止，这些器件在无源腔中存在显着的线性和非线性损耗，限制了可达到的腔尺寸和噪声性能，最终限制了它们的应用范围。在这里，我们利用氮化硅波导的超低损耗来演示具有 755 MHz 窄线间距的异质集成 III-V 氮化硅被动锁模激光器，1 Hz 的射频线宽和低于 200 kHz 的光线宽。此外，这些梳状源采用晶圆级技术制造，因此能够实现低成本和大批量可制造的设备。