Extremely Low Loss Phonon-Trapping Cryogenic Acoustic Cavities for Future Physical Experiments

Low loss Bulk Acoustic Wave devices are considered from the point of view of the solid state approach as phonon-confining cavities. We demonstrate effective design of such acoustic cavities with phonon-trapping techniques exhibiting extremely high quality factors for trapped longitudinally-polarized phonons of various wavelengths. Quality factors of observed modes exceed 1 billion, with a maximum $Q$-factor of 8 billion and $Q\times f$ product of $1.6\cdot10^{18}$ at liquid helium temperatures. Such high sensitivities allow analysis of intrinsic material losses in resonant phonon systems. Various mechanisms of phonon losses are discussed and estimated

About Quartz Crystal Resonator Noise: Recent Study

The first step, before investigating physical origins of noise in resonators, is to investigate correlations between external measurement parameters and the resonator noise. Tests and measurements are mainly performed on an advanced phase noise measurement system, recently set up. The resonator noise is examined as a function of the sensitivity to the drive level, the temperature operating point and the tuning capacitor.Comment: 20th International Conference on Noise and Fluctuations, Pisa : Italie (2009

Quartz resonators thermal modelization using located constants networks

A short recall on recent results about the thermal modelization of quartz resonators is first presented ; next, the method consisting on establishing a located constants network with resistors and capacitors is applyed to the case of a new symmetrical structure of quartz resonator. The designed model is tested by comparison of the experimental frequency versus temperature curves with the calculated ones. By analogy with electrical area, the Bode diagram of the thermal transfer function is obtained. It is pointed out that the new symmetrical structure is particularly insensitive to fast thermal disturbances and may be used with rough ovens. Moreover, with a matched time constant of the structure, a « critical » state appears which permits to rise very quickly the final frequency of the resonator for fast warm up

Parametric model of the BAW resonator phase-noise

International audienceExcepted for the very short terms the frequency stability of ultra-stable oscillators is mainly limited by the resonator noise. In this work we proposed a parametric model of the bulk acoustic wave (BAW) resonator phase noise based on an equivalent circuit. This model explains phase noise generated by a BAW crystal from a point of view of parametric fluctuations and proves the f(-1) dependences of the crystal noise. The model performance is verified with simulation. Simulation results are compared to experimental data and discussed. Comparison of three existing models is made

Precision Close-to-Carrier Phase Noise Simulation of BAW Oscillators

International audienceBased on a commercial simulation tool, the influence of BAW resonator noise on the resulting oscillator phase noise is revisited. The parametric model of the resonator uses experimental data, and includes an f(-2) noise not often considered in measurements, in addition to its flicker noise

Quartz resonators thermal modelization using located constants networks

A short recall on recent results about the thermal modelization of quartz resonators is first presented ; next, the method consisting on establishing a located constants network with resistors and capacitors is applyed to the case of a new symmetrical structure of quartz resonator. The designed model is tested by comparison of the experimental frequency versus temperature curves with the calculated ones. By analogy with electrical area, the Bode diagram of the thermal transfer function is obtained. It is pointed out that the new symmetrical structure is particularly insensitive to fast thermal disturbances and may be used with rough ovens. Moreover, with a matched time constant of the structure, a « critical » state appears which permits to rise very quickly the final frequency of the resonator for fast warm up.Un rappel succinct des résultats récents sur la modélisation thermique des résonateurs à quartz est d'abord présenté; ensuite, la méthode consistant à établir un réseau à constantes localisées à base de résistances et condensateurs est appliquée à une nouvelle structure symétrique de résonateur à quartz. Le modèle construit est testé par comparaison des courbes fréquence-température expérimentales et celles obtenues par le calcul. Le diagramme de Bode de la fonction de transfert thermique est obtenu par analogie électrique. Il apparaît que la nouvelle structure symétrique est particulièrement insensible aux fluctuations rapides de température et qu'une enceinte rudimentaire suffit. De plus, une adaptation de la constante de temps de la structure aboutit à un régime « critique » qui permet d'atteindre rapidement la fréquence finale du résonateur dans le cas d'un chauffage rapide

A parametric quartz crystal oscillator

International audienceParametric oscillators have been well studied but currently are not used often. Nevertheless, they could be a low-phase noise solution, at least outside the frequency bandwidth of the resonant circuit. The theoretical aspect of parametric oscillations is briefly reviewed in this paper. Indeed, the basic theory of a simple resistance-inductor-capacitor (RLC) circuit working in parametric conditions easily can be extended toward a resonant loop that includes a quartz crystal resonator. Then, as an application, this study is transposed to a quartz crystal oscillator that has been modeled and tested as a first ptototype. Simulation results are compared with those actually obtained

Development of a 10 MHz Oscillator Working with an LGT Crystal Resonator : Preliminary results

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Losses in high quality quartz crystal resonators at cryogenic temperatures

International audienceMeasurement of the mechanical losses of quartz crystal is a topic of interest for communities dealing with the gravitational wave detectors and also the time and frequency domain. About the latter, the authors describe Q-factor measurements of quartz crystal resonators at cryogenic temperatures under 10 K, thanks to a cryocooler-based experimental set-up. A Q-factor of 325 millions at 4 K, on the fifth overtone of the quasilongitudinal mode at 15.9 MHz, has been recorded. As shown, the acoustic wave trapping is suspected to limit the Landau-Rumer regime below 6 K [Landau and Rumer, Phys. Z. Sowjetunion 11, 18 (1937)]