Emerging integrated laser technologies in the visible and short near-infrared regimes

Applications in timekeeping, quantum sensing and quantum computing have sparked growing demand for high-performance photonic integrated circuit (PIC) lasers at visible and short near-infrared wavelengths between 400 nm and 1,000 nm. This Review summarizes the application needs and recent advances in such PIC lasers, focusing on low-noise, continuous-wave operation needed for many quantum technologies. We discuss the building blocks for these laser systems, including the heterogeneous and hybrid integration of gain media, low-loss PICs, external-cavity and self-injection locking schemes, and nonlinear wavelength conversion through optical harmonic generation and optical parametric oscillation processes. We review demonstrations utilizing various combinations of these elements. Finally, we consider current PIC laser performance in the context of a few example quantum technologies that require lasers at multiple wavelengths. This Review provides an overview on high-performance photonic integrated circuit lasers at visible and short near-infrared wavelengths between 400 nm and 1,000 nm, focusing on low-noise, continuous-wave operation needed for many quantum technologies.