High-power visible laser via injection locking to a photonic integrated circuit optical parametric oscillator

Abstract

Kerr photonic integrated circuit optical parametric oscillators (PIC OPOs) provide a promising platform for coherent visible-light generation, offering broad wavelength accessibility and low frequency noise for applications in quantum information processing, precision metrology, spectroscopy, and sensing. However, achieving large fiber-coupled output powers and high conversion efficiency remains challenging, impacting the practical deployment of these sources. Here we demonstrate optical injection locking of a commercially available visible Fabry-Pérot (FP) laser diode to a PIC OPO, realizing a hybrid laser that combines the complementary strengths of nonlinear frequency conversion with those of semiconductor laser technologies. Using 25 $\mu$W of injected PIC OPO signal, we generate coherent visible-light at 635 nm with a fiber-coupled output power of $\approx$ 40 mW and side-mode suppression ratio $\gtrsim$ 36.3 dB. The injection-locked FP laser faithfully inherits the low frequency noise characteristics of the PIC OPO signal, achieving a frequency noise floor of 714 Hz${}^2$/Hz. We further demonstrate $\gtrsim 1$ GHz wide locking bandwidths that enable stable injection locking without active PIC OPO stabilization, together with coarse wavelength tunability over 6 nm while preserving both high output power and spectral purity. Our results establish optical injection locking with nonlinear light sources as a compelling option for coherent, high-power, and wavelength-agile integrated coherent visible sources.