Ultra-low-noise hybrid III–V/Si3N4 laser achieving wide-range wavelength switching

Fast wavelength switching plays a crucial role in modern optoelectronic systems, but its demonstration on a chip-scale tunable laser confronts challenges in terms of switching range and linewidth performance. Here, we address these problems by demonstrating a stress-optic-actuated hybrid III–V/Si3N4 laser. The laser distinguishes itself with an external cavity formed by a subwavelength defect assisted microring resonator aligned with an asymmetric Mach–Zehnder interferometer, enabling considerable tunability enhancement as well as high-Q reflection. The demonstrated laser achieves static wavelength tuning from 1513.37 to 1559.53 nm, featuring an intrinsic linewidth of 8.92 Hz that is comparable to the state-of-the-art level. Leveraging the inherent high-speed property of stress-optic actuation, the laser realizes a fast wavelength switching within a wide range of 21.35 nm under single-ring actuation, together with a switching time below 4 μs. Our demonstrated III–V/Si3N4 laser opens up new opportunities in diverse applications from data-center interconnects to light detection and ranging.