A Portable Microwave Clock Using Laser-Cooled Trapped 171 Yb+Ions

A portable microwave clock incorporating laser-cooling of 171 Yb+ promises to bring significantly improved performance compared to existing thermal commercial devices. We report on progress in the development of a compact microwave frequency standard designed to fit in a 19-inch rack enclosure that comprises laser, electronics and physics package subsystems. Recent results in which a local oscillator was disciplined by laser-cooled trapped 171 Yb + ions are presented. Preliminary measurements have demonstrated a fractional frequency instability of $1\times 10^{-13}$ at 10, 000 s. Potential applications include telecommunications and financial operations time reference systems as well as navigation system integrity.