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dc.contributor.authorZhao, S
dc.contributor.authorWithington, S
dc.contributor.authorThomas, CN
dc.date.accessioned2022-06-29T19:46:55Z
dc.date.available2022-06-29T19:46:55Z
dc.date.issued2022
dc.date.submitted2022-02-23
dc.identifier.issn0022-3727
dc.identifier.otherdac782e
dc.identifier.otherac782e
dc.identifier.otherjphysd-130618.r1
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/338529
dc.description.abstractThe underlying nonlinear mechanisms behind the operation of travelling-wave parametric amplifiers (TWPAs) are important in determining their performance in terms of added noise, maximum gain, and bandwidth. We describe a method of characterising the underlying nonlinearity of a superconducting material in terms of its dissipative-reactive ratio and the response time of the underlying microscopic processes. We describe and calculate the different behaviour arising from the equilibrium supercurrent nonlinearity, which has low dissipation and fast response time, and the non-equilibrium heating nonlinearity, which has high dissipation and slow response time. We have fabricated TWPAs based on Al and Ti, and characterised their nonlinearities using our analysis. For both Al and Ti, the measured dissipative-reactive ratios and response times are quantitatively similar to predictions for the non-equilibrium heating nonlinearity. We were able to obtain more than 20 dB of peak power gain, although only over a narrow bandwidth of a few kilohertz. Our method of characterising the underlying nonlinearities could also be useful in the understanding and design of other superconducting nonlinear devices such as parametric up-converters, kinetic inductance Fourier transform spectrometers, and resonator parametric amplifiers.
dc.languageen
dc.publisherIOP Publishing
dc.subjectPaper
dc.subjectCondensed matter
dc.subjectsuperconducting parametric amplifiers
dc.subjectnonlinearity
dc.subjectnon-equilibrium heating
dc.subjectsupercurrent
dc.titleNonlinear mechanisms in Al and Ti superconducting travelling-wave parametric amplifiers
dc.typeArticle
dc.date.updated2022-06-29T19:46:54Z
prism.issueIdentifier36
prism.publicationNameJournal of Physics D: Applied Physics
prism.volume55
dc.identifier.doi10.17863/CAM.85942
dcterms.dateAccepted2022-06-13
rioxxterms.versionofrecord10.1088/1361-6463/ac782e
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0
dc.contributor.orcidZhao, S [0000-0002-5712-6937]
dc.identifier.eissn1361-6463
pubs.funder-project-idSTFC (ST/T006307/1)
cam.issuedOnline2022-06-27


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