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Title: A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2–4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be −23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is −105 dB rad{sup 2}/Hz at 1 kHz offset and −150 dB rad{sup 2}/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10{sup −9} at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10{sup −11} τ{sup −1/2} up to a fewmore » seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance.« less
Authors:
; ; ;  [1]
  1. FEMTO-ST, CNRS, UFC, 26 chemin de l’Epitaphe 25030 Besançon Cedex (France)
Publication Date:
OSTI Identifier:
22482610
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ALUMINIUM; DESIGN; ELECTRIC POTENTIAL; GHZ RANGE 01-100; KHZ RANGE 01-100; NOISE; OSCILLATORS; PHASE SHIFT; RESONATORS; SAPPHIRE; SIGNALS; SIGNAL-TO-NOISE RATIO; SOUND WAVES; TEMPERATURE COEFFICIENT; TRAPPING; TUNING; VAPORS