Compact (few cc volume) and low power consumption (< 200 mW) atomic clocks (also known as Chip-Scale Atomic Clocks, CSAC) have become commercially available in the last decade and have demonstrated their benefits for a wide range of applications, such as PNT in adverse environment (long coherent integration), secure telecommunication or for timing hold-over in case of loss of GNSS or other network signals.
Current CSAC technology relies on miniaturization of atomic resonators using micro-fabricated vapour cells and coherent laser-atom interaction, which results in limited frequency stability performance (1E-10 level at 1 second, 1E-11 level over several minutes to 1 day), temperature sensitivity and challenges in thermal design. Several alternative schemes for miniature atomic clocks have been proposed and evaluated during the past decade in view of improved clock performances. Largely based on high-vacuum atom containers and/or multi-wavelength or high-power laser sources, most of these proposed alternative approaches however come at the expense of more complex clock architectures and more bulky devices with high power consumption.
Based on recent advances in science and technology, the AMICC project aims for evaluating and implementing an alternative but still simple architecture for CSAC, towards about 10-fold improvement in clock stability, and in view of avoiding current issues with CSAC. Pre-studies performed by the contractors indicate that such performance improvements can be achieved when replacing the standard CSAC scheme by direct microwave interrogation of the atoms in the microcell, using a custom-designed miniature microwave resonator. Concepts for a truly miniaturized microwave resonator have been developed previously and will serve as starting point for the AMICC project. Key advantages of the AMICC approach are a simple clock architecture with need for very few key components, limited to one laser, one microcell, and one microwave resonator only, thus enabling a very compact and low-power miniature atomic clock.
The project tasks to be performed will include:

•  Review of the state of the art / technology trade-offs
•  Prototype definition
•  Prototype realisation and test preparation
•  Test and conclusions

The AMICC project will demonstrate and analyse the clock performance improvements achievable with the proposed clock architecture. In the long run, a novel CSAC device with improved stability performance has a great potential for enabling a variety of enhanced PNT applications, both on ground and in space.