Loh William, Gray Dodd, Maxson Ryan, Kharas Dave, Plant Jason, Juodawlkis Paul W, Sorace-Agaskar Cheryl, Yegnanarayanan Siva
MIT Lincoln Laboratory, Lexington, MA, USA.
Nat Commun. 2025 Aug 27;16(1):7997. doi: 10.1038/s41467-025-63369-3.
Photonically-synthesized microwave signals have surpassed the phase-noise performance achievable by traditional means of RF signal generation. However, for microwave-photonic oscillators to truly replace their RF counterparts, this phase-noise advantage must also be realizable when operating outside of a laboratory. Oscillators are known to be notoriously vibration sensitive, with both traditional RF and optical oscillators degrading sharply in all but the most stationary of environments. We demonstrate here a powerful technique that makes use of a precise frequency difference between two optical signals, termed the magic cancellation point, to suppress the vibration-induced noise upon optical frequency division to the RF. We showcase the cancellation of vibration noise by 22.6 dB, achieving an acceleration sensitivity of 1.5 × 10 g. Beyond mitigating the effects of vibration, this technique also preserves the excellent phase noise obtained by optical frequency division and reaches -72 dBc/Hz and -139 dBc/Hz at 10 Hz and 10 kHz offset frequencies on a 10 GHz carrier. This technique applies widely to optical carriers of any center wavelength and derived from an arbitrary resonator geometry.
光子合成微波信号已经超越了传统射频信号生成方式所能达到的相位噪声性能。然而，要使微波光子振荡器真正取代其射频同类产品，这种相位噪声优势在实验室之外运行时也必须能够实现。众所周知，振荡器对振动极其敏感，传统的射频振荡器和光学振荡器在除了最稳定的环境之外的所有环境中都会急剧退化。我们在此展示了一种强大的技术，该技术利用两个光信号之间的精确频率差（称为神奇抵消点）来抑制光频分频到射频时的振动诱导噪声。我们展示了振动噪声被消除22.6 dB，实现了1.5×10⁻⁶g的加速度灵敏度。除了减轻振动的影响之外，该技术还保留了通过光频分频获得的出色相位噪声，在10 GHz载波上，在10 Hz和10 kHz偏移频率处分别达到-72 dBc/Hz和-139 dBc/Hz。该技术广泛适用于任何中心波长且源自任意谐振器几何结构的光载波。
