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A compact, thermal noise limited reference cavity for ultra-low noise microwave generation
Published
Author(s)
Josue Davila-Rodriguez, Frederick N. Baynes, Andrew D. Ludlow, Tara M. Fortier, Holly F. Leopardi, Scott A. Diddams, Franklyn J. Quinlan
Abstract
A 25 mm long, rigidly-held, ultra-stable optical frequency reference cavity is demonstrated. The cavity spacer has an easy-to-manufacture cylindrical shape which nonetheless exhibits a holding geometry predicted to be first-order insensitive to the squeezing force. To decrease the thermal noise limit for such a short cavity the optical beam diameter has been enlarged by increasing the radius of curvature of the curved mirror to 10.2 m. With this configuration, a laser locked to the cavity is predicted to have a thermal noise limited phase noise of -9 dBrad2/Hz at 1 Hz offset from the 280 THz optical carrier, which, after optical frequency division, supports microwave generation at 10 GHz with phase noise near -100 dBc/Hz at 1 Hz offset. Laser phase noise that is nearly thermal noise limited for 3 frequency decades (1 Hz to 1 kHz offset), and supports 10 GHz generation with phase noise 600 Hz, is demonstrated.
Davila-Rodriguez, J.
, Baynes, F.
, Ludlow, A.
, Fortier, T.
, Leopardi, H.
, Diddams, S.
and Quinlan, F.
(2017),
A compact, thermal noise limited reference cavity for ultra-low noise microwave generation, Optics Letters
(Accessed October 14, 2025)