Giuseppe Marra is a Principal Research Scientist in the Time and Frequency department. His specialist area of research expertise is optical frequency metrology, with a focus on dissemination of ultra-stable optical frequencies over optical fibre links, including for comparison of distantly located optical atomic clocks. He is also interested in optical frequency combs and fibre-based laser frequency stabilisation techniques.
Giuseppe undertook his undergraduate studies at the Politecnico di Torino, Italy, and postgraduate studies at the Optoelectronics Research Centre in Southampton, UK and joined NPL in 2002.
Over the last few years, he has been pioneering ultra-stable interferometric techniques over terrestrial and submarine cables for the detection of earthquakes and other environmental signals. This innovative use of the existing submarine cable infrastructure could offer a solution for monitoring the oceans floor, which is currently greatly under-sampled. He has also been working on developing solutions to enable the comparison of optical atomic clocks over intercontinental distances using ocean floor optical cables.
Areas of interest
- Comparison of optical clocks via optical fibre links over continental and inter-continental distances
- Earthquake detection and environmental monitoring using submarine optical fibre cables
- Optical frequency combs and their dissemination over optical fibre links
- Fibre-based techniques for laser frequency stabilisation
- Ultrastable laser interferometry for earthquake detection with terrestrial and submarine cables, Marra G, Clivati C, Luckett R, Tampellini A, Kronjäger J, Wright L, Mura A, Levi F, Robinson S, Xuereb A, Baptie B and Calonico D.,
Science 361, 486 (2018)
- Frequency comb-based time transfer over a 159 km long installed fiber network, M. Lessing, H. S. Margolis, C. T. A. Brown, and G. Marra,
Appl. Phys. Lett. 110, 221101 (2017)
- Dissemination of an optical frequency comb over fiber with 3 × 10−18 fractional accuracy, Giuseppe Marra, Helen S. Margolis, and David J. Richardson,
Opt. Express 20, 1775-1782 (2012)