High-coherence hybrid-integrated 780 nm source by self-injection-locked second-harmonic generation in a high-Q silicon-nitride resonator

TL;DR

This paper demonstrates a high-coherence 780 nm light source generated through self-injection locking of a laser to a silicon nitride resonator, achieving record-low noise and potential for broad visible spectrum applications.

Contribution

It introduces a novel method of generating high-coherence visible light via self-injection locking and second-harmonic generation in a silicon nitride resonator, with unprecedented noise performance.

Findings

Achieved a frequency noise floor of 4 Hz$^2$/Hz at 780 nm.

Successfully generated high-coherence 780 nm light via second-harmonic generation.

Method is adaptable for broad visible and near-visible spectrum signal generation.

Abstract

By self-injection-locking a 1560 nm distributed feedback semiconductor laser to a high-$Q$ silicon nitride resonator, a high-coherence 780 nm second harmonic signal is generated via the photogalvanic-induced second-order nonlinearity. A record-low frequency noise floor of 4 Hz$^2$/Hz is achieved for the 780 nm emission. The approach can be generalized for signal generation over a wide range of visible and near-visible bands.