Using a laser to "cool down" the noise in a microchip oscillator can make it 14 decibels more precise.
April 26, 2026
Original Paper
Ultralow phase noise and thermal noise mitigation in Kerr soliton microwave oscillators via auxiliary laser cooling
SSRN · 6642693
The Takeaway
Microcavity soliton combs are used to create incredibly stable microwave signals for GPS and high-speed data. Heat usually creates thermorefractive noise that limits how accurate these devices can be. This research demonstrated an all-optical method that uses an auxiliary laser to counteract this heat-induced noise. The result is a 14-decibel reduction in interference, pushing the device to a new level of frequency stability. It achieves extreme precision without needing bulky cryogenic cooling systems. This makes high-precision timing technology small enough and robust enough for use in smartphones or satellites.
From the abstract
Thermal noise is one of the primary sources of phase noise in microresonator optical frequency combs, which fundamentally limits the frequency stability of soliton microcombs. In this study, we investigate theoretically and experimentally, an all-optical thermal noise suppression method where the auxiliary laser cooling introduces photothermal negative feedback to mitigate thermal noise and realize high spectral purity soliton microwave oscillation. We reveal a critical auxiliary power, at which