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

ABSTRACT 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 toward 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.