Near ultraviolet photonic integrated lasers based on silicon nitride

TL;DR

This paper reports the first hybrid integrated near-ultraviolet laser using gallium nitride and silicon nitride microresonators, achieving record low wavelengths and significant phase noise reduction for quantum and sensing applications.

Contribution

It introduces a novel hybrid laser platform operating at 410 nm, demonstrating record low wavelength operation and substantial phase noise suppression in the near-ultraviolet spectrum.

Findings

Achieved laser operation at 410 nm wavelength.

Demonstrated over 100-fold phase noise reduction.

Utilized high-Q silicon nitride microresonator for stabilization.

Abstract

Low phase noise lasers based on the combination of III-V semiconductors and silicon photonics are well established in the near-infrared spectral regime. Recent advances in the development of low-loss silicon nitride-based photonic integrated resonators have allowed to outperform bulk external diode and fiber lasers in both phase noise and frequency agility in the 1550 nm-telecommunication window. Here, we demonstrate for the first time a hybrid integrated laser composed of a gallium nitride (GaN) based laser diode and a silicon nitride photonic chip-based microresonator operating at record low wavelengths as low as 410 nm in the near-ultraviolet wavelength region suitable for addressing atomic transitions of atoms and ions used in atomic clocks, quantum computing, or for underwater LiDAR. Using self-injection locking to a high Q (0.4 $\times$ 10$^6$) photonic integrated microresonator we observe a phase noise reduction of the Fabry-P\'erot laser at 461 nm by a factor greater than 100$\times$, limited by the device quality factor and back-reflection.