New generation of frequency standards for industry

Increasing telecommunication speeds and improved technologies are required to continue to meet business and consumer needs. Better time and frequency synchronisation is essential to meet these needs and requires the generation of new reference standards that are compact, robust and well-suited for operation in industrial environments.

Atomic clocks provide frequency standards and current atomic clocks already meet laboratory performance requirements; however, they need to be smaller and capable of operating in harsh environments to be used in industrial applications. This project focused on improving the robustness and portability of high-frequency atomic clocks for applications in space, aerospace, defence, astronomy, and optical and microwave communications. The project developed:

• New gas-filled hollow-core fibre (HCF) prototype optical frequency standards. These were produced in partnership with industrial collaborators who provide wavelength standards for the optical communications industry.
• Novel local optical oscillator architectures using both small cubic optical cavities and fibre spool interferometers.
• Demonstrators for the performance of two practical approaches to microwave frequency standards – trapped atom-on-a-chip and miniature caesium-filled clocks in hollow-core fibre. This included the first-ever accuracy evaluation of a miniature microwave clock with cold trapped atoms.

These results support the development of more stable, accurate clocks and improved synchronisation between them that will enable higher-speed data transfer with fewer errors and provide more reliable systems for industry and consumers. The industrial deployment of improved clocks rests upon the further refinement of system and device designs, and European SMEs are already developing some of the project’s outputs – a licence for the optical cubic cavity has been agreed and a collaboration to develop the fibre spool interferometer has been established. The European Space Agency is also interested in the small, robust clocks being developed both for satellite-based atmospheric monitoring and for the STE-QUEST mission that aims to answer a range of questions in fundamental physics.