Ultra-low vibration pulse-tube cryocooler stabilized cryogenic sapphire oscillator with notation 10-16 fractional frequency stability

John G. Hartnett, Nitin R. Nand

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

A low maintenance long-term operational cryogenic sapphire oscillator has been implemented at 11.2 GHz using an ultra-low-vibration cryostat and pulse-tube cryocooler. It is currently the world's most stable microwave oscillator employing a cryocooler. Its performance is explained in terms of temperature and frequency stability. The phase noise and the Allan deviation of frequency fluctuations have been evaluated by comparing it to an ultra-stable liquid-helium cooled cryogenic sapphire oscillator in the same laboratory. Assuming both contribute equally, the Allan deviation evaluated for the cryocooled oscillator is σ-y 1 × 10 -15τ-1/2 for integration times 1 < τ < 10 s with a minimum σy = 3.9 × 10-16 at τ = 20 s. The long term frequency drift is less than 5 × 10-14day. From the measured power spectral density of phase fluctuations, the single-sideband phase noise can be represented by L (f) = 10-14.0/ f4+10-11.6/f3+10-10.0/f 2+10-10.2/f+ 10-11.0 rad2/Hz for Fourier frequencies 10-3 < f < 103 Hz in the single oscillator. As a result, L\approx -97.5 dBc/Hz at 1-Hz offset from the carrier.

Original languageEnglish
Article number5617322
Pages (from-to)3580-3586
Number of pages7
JournalIEEE Transactions on Microwave Theory and Techniques
Volume58
Issue number12 PART 1
DOIs
Publication statusPublished - Dec 2010

Keywords

  • Cryocooler
  • cryogenic sapphire oscillator
  • frequency stability
  • phase noise

Fingerprint

Dive into the research topics of 'Ultra-low vibration pulse-tube cryocooler stabilized cryogenic sapphire oscillator with notation 10-16 fractional frequency stability'. Together they form a unique fingerprint.

Cite this