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

摘要

We demonstrate feedback and harmonic locking of chip-scale slot-typeoptomechanical oscillators to external low-noise reference clocks, withsuppressed timing jitter by three orders of magnitude. The feedback andcompensation techniques significantly reduce the close-to-carrier phase noise,especially within the locking bandwidth for the integral root-mean-squaretiming jitter. Harmonic locking via high-order carrier signals is alsodemonstrated with similar phase noise and integrated root-mean-square timingjitter reduction. The chip-scale optomechanical oscillators are tunable over an80-kHz range by tracking the reference clock, with potential applications intunable radio-frequency photonics platforms.