Wide range tunable photonic frequency synthesiser with low and non-scaling phase noise

Wide range tunable photonic frequency synthesiser with low and non-scaling phase noise | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Wide range tunable photonic frequency synthesiser with low and non-scaling phase noise Zhixin Liu, Amany Kassem, Zichuan Zhou, Alex Bennett, Izzat Darwazeh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8888348/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Frequency synthesis is central to communications, sensing, navigation and spectroscopy, requiring low phase noise and wide frequency tunability from microwave to millimetre-wave bands. However, conventional electronic frequency synthesis suffers from phase noise that scales quadratically with output frequency and from intrinsically limited tuning bandwidth, leading to bulky, power-hungry architectures at high frequencies. Many photonic approaches achieve low phase noise with ultra-stable lasers and optical frequency combs, but typically lack wide tunability and impose size, weight and power constraints. Here we demonstrate a photonic frequency synthesiser based on an optical harmonic locking that overcomes these limitations by locking widely spaced narrow-linewidth lasers using only low-frequency, low-bandwidth electronics. The approach enables continuous, referenced frequency generation with Hz-level resolution from 0.375 to 170 GHz, while exhibiting non-scaling phase noise over offset frequencies from 200kHz to 10MHz. We record a phase noise of −146 dBrad2/Hz at 10MHz offset, and a fractional frequency instability of 3×10−13 at 1s, resulting in a reduction of timing jitter with increasing carrier frequency 11fs at 170GHz, outperforming state-of-the-art commercial signal generators. We further demonstrate 1024-QAM transmission at a 150GHz carrier, highlighting the potential of photonic synthesis for next-generation high-frequency communication and sensing systems. The architecture is compatible with integrated photonic implementations, promising potential chip-scale deployment. Physical sciences/Optics and photonics/Applied optics/Microwave photonics Physical sciences/Optics and photonics/Applied optics/Optoelectronic devices and components Physical sciences/Optics and photonics/Other photonics/Frequency combs Full Text Additional Declarations Yes there is potential Competing Interest. A.K. and Z.L. are inventors on patent application No. PCT/EP2025/057707 related to the subject matter of this work. Supplementary Files supplementary.pdf Supplementary material Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8888348","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":607551508,"identity":"b2a833e6-7903-4e87-a16a-e599ba5700f6","order_by":0,"name":"Zhixin 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However, conventional electronic frequency synthesis suffers from phase noise that scales quadratically with output frequency and from intrinsically limited tuning bandwidth, leading to bulky, power-hungry architectures at high frequencies. Many photonic approaches achieve low phase noise with ultra-stable lasers and optical frequency combs, but typically lack wide tunability and impose size, weight and power constraints. Here we demonstrate a photonic frequency synthesiser based on an optical harmonic locking that overcomes these limitations by locking widely spaced narrow-linewidth lasers using only low-frequency, low-bandwidth electronics. The approach enables continuous, referenced frequency generation with Hz-level resolution from 0.375 to 170 GHz, while exhibiting non-scaling phase noise over offset frequencies from 200kHz to 10MHz. 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