David Moss and his colleagues set a world record in 2020: the fastest data transmission down an optical fibre from a single chip. Published in Nature Communications, the paper on this record-setting research almost immediately attracted huge world-wide attention. Moss first saw an article about it on the BBC website and it took a few seconds before he realised it was about his research. “It got a lot of traction, which was a bit of a surprise,” he says of the mainstream media attention.
Now a distinguished professor of photonics and the director of the optical sciences centre at Swinburne University, he is also deputy director of the newly-funded Australian Research Council Centre of Excellence called COMBS: the Centre for Optical Microcombs for Breakthrough Science.
Born and educated in Canada, with a doctorate from Toronto University, Moss gravitated to physics, he says, after he decided mathematics was too difficult. As a child he had a vague idea of becoming an astronomer but toward the end of his undergraduate degree he met his future doctorate supervisor and developed an interest in lasers and then photonics.
Photonics might not be very well known or understood, he says, but it’s foundational to our modern world. “In a sense it’s right under everyone’s nose because the very fabric of the internet we use every day is laser-based, it’s optical fibre and high-speed lasers,” he says. “It’s enabled the modern technological society, the internet and communications, that almost defines our modern age.”
From photonics Moss moved into exploring the potential of optical microcombs, where he has been working for 15 years. Simply put, a microcomb is a regular array of precisely spaced frequencies of light, like the teeth of a comb, he says.
Optical clocks, which are 100,000 times more accurate than anything else we have developed, are now based on optical frequency combs, and ultimately, he believes, they will be based on optical microcomb chips. “It sounds boring but it’s actually incredibly enabling to be able to measure time to that accuracy,” Moss says. “Time is fundamental – the base we measure everything else from.”
Almost all optical measurements use light frequencies and the microcomb is almost infinitely adaptable, with applications ranging from bio-related imaging to space exploration: astrocombs, for instance, are a type of frequency comb used to increase the accuracy of astronomical observations.
“Now it’s getting to the point where we’re using it for all kinds of different applications, and one is astrocombs for calibrating astronomical spectra,” he says. “I find myself working with our astronomers and astrophysicists and so I may end up getting some papers in astronomy after all, after all these years.”
Moss first came to Australia in 1994 to take up a position with Sydney University but after a couple of years the telecom boom took hold and scientists left academia in droves to make their fortunes. He went back to Canada and worked in the private sector, he says, until “the music stopped, which it did very dramatically and very abruptly, in 2002”.
He came back to Sydney University to join one of the first ARC centres of excellence which was just then starting, CUDOS: the Centre for Ultra High Bandwidth Devices for Optical Systems. He’s been in Australia ever since, exploring the frontiers of microcomb science and its many applications. “I really think these microcombs are going to be a gamechanger.”