Development of an Industrial Two-Photon Rb Atomic Clock for Timekeeping Applications

The performance of a two-photon atomic clock currently developed at CSEM in partnership with Rolex is reported. This clock, designed in view of its integration in a 19-inch rack-mount enclosure, is intended for 24/7 operation as Rolex timescales master clock. Its design, based on a standard architecture, takes advantage of the high-reliability and high-availability of telecom C-band components. Long-term stability limited to a few 10^-15 by the cell helium permeation drift is demonstrated. A drift-removed relative frequency stability in the 10^-15 range at 10⁵ s and beyond is achieved, limited by the residual AC Stark-shift.