We describe recent efforts at NIST to develop microfabricated, chip-scale atomic frequency references based on microfabrication techniques commonly used in micro electro mechanical systems (MEMS). These devices are projected to have a volume of 1 cm3, a power dissipation of 30 mW and a fractional frequency instability of 10-11 at one hour of integration. To date, we have demonstrated the three critical subsystems of a frequency reference of this type with a total volume below 10 cm3, a total power dissipation below 200 mW and a fractional frequency instability below 6x10-10/√τ. The physics package subsystem is fabricated and assembled using MEMS processing techniques, which allow unprecedented reductions in the size and power of this component. The local oscillator subsystem, which is locked to the physics package resonance, is based on a micro-coaxial resonator. It has a footprint of 0.5 cm3, runs on as little as 2 mW of DC electrical power, and is stable enough to be locked to the physics package with a frequency instability below 2x10- 10/√τ. Finally, compact control electronics currently based on an analog demodulator chip, but likely to be replaced by a microprocessor, runs locks the LO to the physics package.
Proceedings Title: Proc. 2005 ION-GNSS Conf.
Pub Type: Conferences
atomic clock, atomic frequency reference, coherent population trapping, MEMS, micromachining