A stabilized chip-scale Kerr frequency comb via a high-Q reference photonic microresonator

TL;DR

This paper demonstrates a chip-scale stabilized Kerr frequency comb by locking a pump laser to a high-Q microresonator and stabilizing the comb spacing with an external microwave oscillator, advancing miniaturization.

Contribution

It introduces a method to stabilize a Kerr comb on-chip by integrating a high-Q microresonator as a reference, reducing the impact of pump laser shifts.

Findings

Fractional instability limited by microwave oscillator below 1 s

Long-term stability affected by pump laser drift

Potential for on-chip integration of the microresonator reference

Abstract

We stabilize a chip-scale Si3N4 phase-locked Kerr frequency comb via locking the pump laser to an independent stable high-Q reference microresonator and locking the comb spacing to an external microwave oscillator. In this comb, the pump laser shift induces negligible impact on the comb spacing change. This scheme is a step towards miniaturization of the stabilized Kerr comb system as the microresonator reference can potentially be integrated on-chip. Fractional instability of the optical harmonics of the stabilized comb is limited by the microwave oscillator used for comb spacing lock below 1 s averaging time and coincides with the pump laser drift in the long term.