IN BRIEF The rooftop observatory at The University of Western Australia. Credit: ICRAR/ UWA.
SKA SYNCHRONISATION TECHNOLOGY LEADS TO WORLD’S MOST STABLE LASER TRANSMISSION BY ICRAR COMMUNICATIONS TEAM In a study published in the journal Nature Communications, ICRAR researchers have teamed up with colleagues from the French National Centre for Space Studies (CNES) and the French metrology lab Systèmes de Référence Temps-Espace (SYRTE) to set a world record for the most stable transmission of a laser signal through the atmosphere. “By combining our phase stabilisation technology with advanced self-guiding optical terminals we were able to send a laser signal from one point to another without interference from atmospheric turbulence,” said lead author Benjamin Dix-Matthews, a PhD student at ICRAR and The University of Western Australia. “It’s as if the moving atmosphere has been removed and doesn’t exist. It allows us to send highly-stable laser signals through the atmosphere while retaining the quality of the original signal,” he added. In 2017, a similar optical fibre-based synchronisation distribution system designed by the team was selected for SKA-Mid dishes in South Africa. The long distances between the SKA antennas mean radio waves from the sky reach each antenna at different times. To achieve the performance demanded by the SKA science cases, the signals must be
aligned with extreme precision so they can be successfully combined by the SKA’s supercomputers. It has now led to the world’s most precise method for comparing the flow of time between two separate locations using a laser system transmitted through the atmosphere. ICRAR-UWA senior researcher Dr Sascha Schediwy said the technology’s precise measurements also have practical uses in earth science and geophysics. “This technology could improve satellite-based studies of how the water table changes over time, or to look for ore deposits underground,” Dr Schediwy said. There are further potential benefits for optical communications, an emerging field that uses light to carry information. Optical communications can securely transmit data between satellites and Earth with much higher data rates than current radio communications. “Our technology could help us increase the data rate from satellites to ground by orders of magnitude,” Dr Schediwy said. “The next generation of big data-gathering satellites would be able to get critical information to the ground faster.” Above: Members of the project team standing in front of a telescope dome located at the CNES campus in Toulouse, containing one of the self-guiding optical terminals. Credit: ICRAR/UWA. Far Left: A schematic view of our point-to-point atmosphericstabilised optical link between two buildings at the CNES campus in Toulouse. Left: One of the self-guiding optical terminals on its telescope mount, and the phase-stabilisation Transmitter Module and Receiver Module. Credit: ICRAR/UWA.
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