title: Cryogenic sapphire oscillator using a low-vibration design pulse-tube cryocooler: first results.
abstract: A cryogenic sapphire oscillator (CSO) has been implemented at 11.2 GHz using a low-vibration design pulsetube cryocooler. Compared with a state-of-the-art liquid helium cooled CSO in the same laboratory, the square root Allan variance of their combined fractional frequency instability is sigma(y) = 1.4 x 10(-15)tau(-1/2) for integration times 1 < tau < 10 s, dominated by white frequency noise. The minimum sigmay = 5.3 x 10(-16) for the two oscillators was reached at tau = 20 s. Assuming equal contributions from both CSOs, the single oscillator phase noise S(phi) approximately -96 dB x rad(2)/Hz at 1 Hz set from the carrier.
authors.affiliation: Schoolof Physics, University of Western Australia, Crawley, W.A., Australia. john@physics.uwa.edu.au
authors.forename: John
authors.initials: J
authors.lastname: Hartnett
authors.forename: Nitin
authors.initials: N
authors.lastname: Nand
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Floch