title: Absolute frequency measurement of a 1.5-microm acetylene standard by use of a combined frequency chain and femtosecond comb.
abstract: We have developed and characterized a pair of Doppler-free acetylene-stabilized diode laser frequency standards as optical communications references. The Allan deviation sigma/f of an individual system reaches a minimum of 4 x 10(-14) at a sampling time of 5000 s, and the long-term lock-point repeatability is found to be 0.4 kHz (one standard uncertainty), corresponding to a fractional uncertainty of 2 x 10(-12). Using a combination of a frequency chain and a self-referenced femtosecond comb, we have measured the frequency of line P(16) of the v1 + v3 overtone band of 13C2H2 to be 194,369,569,385.9 (3.0) kHz. The uncertainty of this number is limited solely by the reproducibility of the standards.
authors.affiliation: National Physical Laboratory, Queens Road, Teddington, Middlesex TW11 0LW, UK. christopher.edwards@npl.co.uk
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Edwards
authors.forename: Helen S
authors.initials: HS
authors.lastname: Margolis
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Barwood
authors.forename: Stephen N
authors.initials: SN
authors.lastname: Lea
authors.forename: Patrick
authors.initials: P
authors.lastname: Gill
authors.forename: Guilong
authors.initials: G
authors.lastname: Huang
authors.forename: William R C
authors.initials: WR
authors.lastname: Rowley