Impact of the frequency drift of a laser cooler on the phase noise of the microcomb repetition frequency
Year: 2025
Type: article
Abstract: We study the repetition frequency phase-noise in an auxiliary laser cooler assisted soliton microcomb formed in a high-Q Si₃N₄ microresonator. We find that, below a 1-kHz offset from the carrier, this noise is dominated by the frequency drift of the laser cooler. We identify the dominant noise types in the phase-noise spectrum of the repetition frequency using the polynomial law and relate the underlying noise sources that lead to the phase instability. We find that the 1 𝑓³ ⁄ noise dominates the repetition frequency phase-noise over three decades, which we attribute to the frequency drift of the laser cooler and the uncompensated cavity-pump detuning. Since the laser cooler acts on the cavity-pump detuning via the thermo-optic effect, the thermal response time of the cavity limits the filtering of 1 𝑓³ ⁄ noise originating from the free-running pump laser. Hence, low-phase-noise operation that is obtained by using the auxiliary laser cooling scheme requires both the pump and cooler lasers to be locked to a stable frequency reference.
DOI: 10.13016/m2mghr-bjbu
Authors: Mahmood, Tanvir, Cahill, James P., Sykes, Patrick, Menyuk, Curtis, Zhou, Weimin
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6903432762
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