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Title: Simple-design ultra-low phase noise microwave frequency synthesizers for high-performing Cs and Rb vapor-cell atomic clocks

We report on the development and characterization of novel 4.596 GHz and 6.834 GHz microwave frequency synthesizers devoted to be used as local oscillators in high-performance Cs and Rb vapor-cell atomic clocks. The key element of the synthesizers is a custom module that integrates a high spectral purity 100 MHz oven controlled quartz crystal oscillator frequency-multiplied to 1.6 GHz with minor excess noise. Frequency multiplication, division, and mixing stages are then implemented to generate the exact output atomic resonance frequencies. Absolute phase noise performances of the output 4.596 GHz signal are measured to be −109 and −141 dB rad{sup 2}/Hz at 100 Hz and 10 kHz Fourier frequencies, respectively. The phase noise of the 6.834 GHz signal is −105 and −138 dB rad{sup 2}/Hz at 100 Hz and 10 kHz offset frequencies, respectively. The performances of the synthesis chains contribute to the atomic clock short term fractional frequency stability at a level of 3.1 × 10{sup −14} for the Cs cell clock and 2 × 10{sup −14} for the Rb clock at 1 s averaging time. This value is comparable with the clock shot noise limit. We describe the residual phase noise measurements of key components and stages to identifymore » the main limitations of the synthesis chains. The residual frequency stability of synthesis chains is measured to be at the 10{sup −15} level for 1 s integration time. Relevant advantages of the synthesis design, using only commercially available components, are to combine excellent phase noise performances, simple-architecture, low-cost, and to be easily customized for signal output generation at 4.596 GHz or 6.834 GHz for applications to Cs or Rb vapor-cell frequency standards.« less
Authors:
 [1] ;  [2] ; ;  [3] ; ;  [1]
  1. FEMTO-ST, CNRS, Université de Franche-Comté, 26 chemin de l’Epitaphe, 25030 Besançon (France)
  2. (Italy)
  3. INRIM, Strada delle Cacce 91, 10135 Torino (Italy)
Publication Date:
OSTI Identifier:
22482793
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 9; 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; ATOMIC CLOCKS; CRYSTALS; DESIGN; GHZ RANGE 01-100; KHZ RANGE 01-100; MICROWAVE RADIATION; NOISE; OSCILLATORS; OVENS; PERFORMANCE; QUARTZ; RADIATION DOSE UNITS; SIGNALS; VAPORS