Micro-Transfer Printed Continuous-Wave and Mode-Locked Laser Integration at 800 nm on a Silicon Nitride Platform

Applications such as augmented and virtual reality (AR/VR), optical atomic clocks, and quantum computing require photonic integration of (near-)visible laser sources to enable commercialization at scale. The heterogeneous integration of III-V optical gain materials with low-loss silicon nitride waveguides enables complex photonic circuits with low-noise lasers on a single chip. Previous such demonstrations are mostly geared towards telecommunication wavelengths. At shorter wavelengths, limited options exist for efficient light coupling between III-V and silicon nitride waveguides. Recent advances in wafer-bonded devices at these wavelengths require complex coupling structures and suffer from poor heat dissipation. Here, we overcome these challenges and demonstrate a wafer-scale micro-transfer printing method integrating functional III-V devices directly onto the silicon substrate of a commercial silicon nitride platform. We show butt-coupling of efficient GaAs-based amplifiers operating at 800 nm with integrated saturable absorbers to silicon nitride cavities. This resulted in extended-cavity continuous-wave and mode-locked lasers generating pulse trains with repetition rates ranging from 3.2 to 9.2 GHz and excellent passive stability with a fundamental radio-frequency linewidth of 519 Hz. These results show the potential to build complex, high-performance fully-integrated laser systems at 800 nm using scalable manufacturing, promising advances for AR/VR, nonlinear photonics, timekeeping, quantum computing, and beyond.