Making light work of communications

As early as the 1850s light beams were funneled through streams of water to create fantastically coloured fountains, a curiosity for the public. At that time a future of high-speed communications built upon this basic technology was beyond the comprehension of physicists. 

That future is now. With the use of fibre-optic cables internet signals flash around the globe in milliseconds. Developed from traditional optics technology, photonics is the study and manipulation of the basic components of light: photons. 

Even though the use of photonics is commonplace, researchers in the Faculty of Science are out to harness light and develop the next generation of photonic devices. Work in this bright field is united under the Institute of Photonics and Optical Science (IPOS).  

IPOS researchers, unleash photonics on a range of experimental technologies including those for telecommunications, biomedicine, astrophysics and the sensing power of security devices. 

Professor Ben Eggleton, founding director of the Centre for Ultra-high Bandwidth Devices for Optical Systems (CUDOS) and co -director of the NSW Smart Sensing Network, is on a mission to revolutionise communication systems with the photonic chip.  

“Signals from optic fibres are slowed when they reach copper based electrical switches: it takes time to convert the data-rich optical signals to an electrical format.”  

Eggleton’s all-optical signal processing overcomes this electronic speed hump and will vastly increase the speed of the internet. 

To do this, Eggleton turned the field of communications on its head, exploiting a common problem in fibre-optic communication: nonlinearities. 

A nonlinear material will undergo a transformation of its properties when exposed to intense light, distorting signal transmission and potentially corrupting information. Even when these distortions are minor, they become amplified when signals travel over long distances. 

However, processing of signals at the end of the fibres involves complex changes, such as amplification, and this is precisely where Eggleton made use of the normally meddling influence of nonlinearity.  

“The key to CUDOS’ research is to investigate new materials that exhibit massive optical nonlinearities and use them for complex signal processing.” 

Silica optical fibres used in standard communication chips are not ideal for making compact devices. Using chalcogenide glass, Eggleton and team create smaller chips hundreds of times stronger than silicon devices. 

“We’ve created materials with the greatest nonlinear optical capability ever demonstrated.” 

“Implanted in new devices they have drastically improved communications systems, allowing tunable optics and enabling the transfer of data at a faster rate.” 

Eggleton has extended his work to microfluidics, that manipulates fluids in minute volumes.  

“Liquids add a layer of control to photonic devices, increasing our ability to fine tune their interactions with light.” 

“Photonic crystals are the backbone of this technology, increasing precision and providing the potential to be reversible,” explains Eggleton. 

With increased sensitivity this technology has refined laboratory and medical equipment and has in turn improved healthcare in Australia. 

Light slows down as it passes from the air into another medium, and as it slows it bends to a degree that is unique to each medium. Microfluidic cavities make this unique degree of bend, known as the refractive index, observable.  

With this technology scientists can monitor changes in reactant concentration or even a patient’s health. 

Eggleton was recently appointed the Director of the University of Sydney Nano Institute – a multi-disciplinary research centre established in 2016. The centre’s research spans energy and the environment; health and medicine; communications, computing and security. 

His insights into nanoscale technologies and quantum engineering will be invaluable in propelling the University and the wider community forward into the future.