Local Oscillator Induces Instabilities in Trapped Ion Frequency Standards

Peter D. D. Schwindt, Yuan‐Yu Jau, Heather L. Partner +14 more

We describe the development and frequency instability measurements of a highly miniaturized, buffer gas cooled, trapped-ion atomic clock. The clock utilizes the 12.6 GHz hyperfine transition of the171Yb+ion. A custom-built 3 cm3vacuum package containing the ion trap is integrated with other key elements of the atomic frequency standard, including a photo multiplier tube, miniaturized laser sources at 369 nm and 935 nm, a local oscillator, and control electronics. With the clock physics package assembled on a 10 cm × 15 cm breadboard, the long-term fractional frequency instability was measured to be 6 × 10-14at 25 days of integration. Later, the clock physics package was further miniaturized, and the frequency instability was measured to be 2 × 10-11/τ1/2at integration times up to 10,000 s.

Lute Maleki

G.J. Dick, John D. Prestage

Proposed scheme for enhancing performances of atomic frequency-standard apparatuses calls for two or more ion traps per apparatus interrogated in alternation by radio-frequency pulses. Provides nearly constant feedback gain, thereby providing nearly constant corrections for fluctuations in frequency of local oscillator. Degradation of performance by fluctuations in local oscillators reduced.

Florian Leupold

G.J. Dick, D. A. Stowers

An experimental test of Local-Oscillator (L.O.) degradation of time-sequential passive oscillator performance was accomplished using the TAG-controlled crystal oscillator described in an accompanying paper. For this quantitative demonstration, an electronic frequency-counter discriminator replaced the trapped ion physics package in a closed-loop experiment. With a 10 second cycle time and 5 second dead time, L.O. limited stability was demonstrated in excellent agreement with theoretical calculations. The results are also in agreement with computer simulations and confirm previous noise analysis for the case of a passive standard with short pulse "Ramsey" interrogation.

Piet O. Schmidt, Ian D. Leroux