Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators

Cryogenic sapphire oscillators (CSO) typically require frequency stabilization and noise reduction servos to achieve ultra-high frequency stability and ultra-low phase noise. In order to analyze the performance of a 10.8 GHz frequency-locked CSO and determine the system’s limits, an exten...

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Main Authors: Encai Zhong, J.-M. Le Floch, Hongli Liu, Ke Deng, Jie Zhang, Zehuang Lu
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/11050383/
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author Encai Zhong
J.-M. Le Floch
Hongli Liu
Ke Deng
Jie Zhang
Zehuang Lu
author_facet Encai Zhong
J.-M. Le Floch
Hongli Liu
Ke Deng
Jie Zhang
Zehuang Lu
author_sort Encai Zhong
collection DOAJ
description Cryogenic sapphire oscillators (CSO) typically require frequency stabilization and noise reduction servos to achieve ultra-high frequency stability and ultra-low phase noise. In order to analyze the performance of a 10.8 GHz frequency-locked CSO and determine the system&#x2019;s limits, an extended phase noise model based on Leeson&#x2019;s framework is utilized. This model accounts for noise from the locking system and variations in power and temperature. The results align well with predictions, showing that the phase noise can be reduced from &#x2212;75 dBc/Hz in a free-running state to &#x2212;95 dBc/Hz in a locked state at an offset frequency of 1 Hz. The analysis revealed that the fractional frequency stability of the frequency-locked CSO is limited to <inline-formula> <tex-math notation="LaTeX">$4\times 10^{-15}$ </tex-math></inline-formula> at 1-second averaging time, primarily due to power fluctuations within the sapphire-loaded cavity. With the insights gained from this phase noise model, it is possible to further improve the performance of CSOs in the future.
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institution Kabale University
issn 2169-3536
language English
publishDate 2025-01-01
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spelling doaj-art-9cc13af7518947cd8121b452fba3aa0a2025-08-20T03:28:52ZengIEEEIEEE Access2169-35362025-01-011311081311082010.1109/ACCESS.2025.358297111050383Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire OscillatorsEncai Zhong0https://orcid.org/0009-0005-0098-5748J.-M. Le Floch1https://orcid.org/0000-0003-1537-5561Hongli Liu2https://orcid.org/0000-0001-7118-4220Ke Deng3https://orcid.org/0000-0001-9306-7391Jie Zhang4https://orcid.org/0000-0003-2885-8837Zehuang Lu5https://orcid.org/0000-0002-2800-325XNational Gravitation Laboratory, Huazhong University of Science and Technology, Wuhan, ChinaNational Gravitation Laboratory, Huazhong University of Science and Technology, Wuhan, ChinaNational Gravitation Laboratory, Huazhong University of Science and Technology, Wuhan, ChinaNational Gravitation Laboratory, Huazhong University of Science and Technology, Wuhan, ChinaNational Gravitation Laboratory, Huazhong University of Science and Technology, Wuhan, ChinaNational Gravitation Laboratory, Huazhong University of Science and Technology, Wuhan, ChinaCryogenic sapphire oscillators (CSO) typically require frequency stabilization and noise reduction servos to achieve ultra-high frequency stability and ultra-low phase noise. In order to analyze the performance of a 10.8 GHz frequency-locked CSO and determine the system&#x2019;s limits, an extended phase noise model based on Leeson&#x2019;s framework is utilized. This model accounts for noise from the locking system and variations in power and temperature. The results align well with predictions, showing that the phase noise can be reduced from &#x2212;75 dBc/Hz in a free-running state to &#x2212;95 dBc/Hz in a locked state at an offset frequency of 1 Hz. The analysis revealed that the fractional frequency stability of the frequency-locked CSO is limited to <inline-formula> <tex-math notation="LaTeX">$4\times 10^{-15}$ </tex-math></inline-formula> at 1-second averaging time, primarily due to power fluctuations within the sapphire-loaded cavity. With the insights gained from this phase noise model, it is possible to further improve the performance of CSOs in the future.https://ieeexplore.ieee.org/document/11050383/Cryogenic sapphire oscillatorphase noisefrequency stabilitynoise model
spellingShingle Encai Zhong
J.-M. Le Floch
Hongli Liu
Ke Deng
Jie Zhang
Zehuang Lu
Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators
IEEE Access
Cryogenic sapphire oscillator
phase noise
frequency stability
noise model
title Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators
title_full Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators
title_fullStr Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators
title_full_unstemmed Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators
title_short Analysis of the Phase Noise for Frequency Controlled Cryogenic Sapphire Oscillators
title_sort analysis of the phase noise for frequency controlled cryogenic sapphire oscillators
topic Cryogenic sapphire oscillator
phase noise
frequency stability
noise model
url https://ieeexplore.ieee.org/document/11050383/
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