Feedback and harmonic locking of slot-type optomechanical oscillators to external low-noise reference clocks

TL;DR

This paper demonstrates feedback and harmonic locking of chip-scale optomechanical oscillators to external clocks, significantly reducing timing jitter and phase noise, with potential for tunable RF photonics applications.

Contribution

It introduces techniques for locking optomechanical oscillators to external references, achieving substantial noise reduction and tunability.

Findings

Timing jitter suppressed by three orders of magnitude.

Harmonic locking achieves similar phase noise reduction.

Oscillators tunable over 80 kHz range.

Abstract

We demonstrate feedback and harmonic locking of chip-scale slot-type optomechanical oscillators to external low-noise reference clocks, with suppressed timing jitter by three orders of magnitude. The feedback and compensation techniques significantly reduce the close-to-carrier phase noise, especially within the locking bandwidth for the integral root-mean-square timing jitter. Harmonic locking via high-order carrier signals is also demonstrated with similar phase noise and integrated root-mean-square timing jitter reduction. The chip-scale optomechanical oscillators are tunable over an 80-kHz range by tracking the reference clock, with potential applications in tunable radio-frequency photonics platforms.