Session P1b: Environmental Sensitivity of Clocks and Timing Systems

Turn-Key Deployable and Ultrastable Oscillator with <4E-15 Absolute Stability at 1s, Long-Term Steerable to MW or Optical Atomic Clocks
Michele Giunta, Menlo Systems GmbH, Max-Planck-Institut für Quantenoptik; Benjamin Rauf, Menlo Systems GmbH; Cecilia Clivati, Claudio Calosso, Marco Pizzocaro, Filippo Levi, INRiM; Marc Fischer, Menlo Systems GmbH; Davide Calonico, INRiM; Ronald Holzwarth, Menlo Systems GmbH, Max-Planck-Institut für Quantenoptik
Location: Seaview A/B
Date/Time: Tuesday, Jan. 28, 5:30 p.m.

We present a transportable and turn-key ultrastable oscillator, built in a rack-mount one-meter cube assembly, entailing an ultrastable laser, a frequency comb divider, and MW/RF extraction unit to synthesize 100 MHz, 10 GHz, and 194.4 THz stable and phase-coherent output frequencies. The resulting absolute fractional frequency stability of all output frequencies is <4E-15 (at 1s), and we show the possibility of steering the outputs to a hydrogen maser.
In order to characterize the fractional frequency instability and the close-to-carrier phase noise in absolute terms, we have conducted cross-correlation measurements using a separate independent photonic microwave setup also composed of an ultrastable laser and a frequency comb and, as a third oscillator, a cryogenic sapphire oscillator, both exhibiting similar stability levels in the short term. Furthermore, we show the long-term steering of the RF/MW outputs against the Maser, demonstrating the possibility of enhancing the short-term stability attainable with state-of-the-art active hydrogen masers by more than an order of magnitude.
We will present the result and detail the measurement campaign performed at the National Metrology Institute of Italy.