January 31, 2014

Physics breakthrough paves the way for next generation communications

An international team of researchers has combined fundamental ideas of quantum mechanics with modern optical technology to take light on a one-way trip for the first time.  

The physics breakthrough, which works in a similar way to one-way sunglasses – the person wearing the glasses can see out, but others can’t see in – was published in Nature Communications yesterday (Thursday 30 January).

Lead author Dr Enbang Li, from the University of Wollongong’s School of Physics, said the results pointed to new possibilities to control and manipulate light, which could have various critical applications in defence, sensing, and telecommunications in the future.

“Through normal optical materials (like glass, water or Perspex) and optical systems (like the rear view mirrors in your car), if I can see you, then you can also see me. This is because that the above mentioned materials and systems are reciprocal (like a two-way road),” Dr Li said.

“By using the photonics effect discovered in this research, we can build optical materials and systems through which I can see you, but you cannot see me, that is what we called optical isolation.

“Optical isolators play very important roles in photonic technologies. For example, fibre-optic communications systems (like our NBN) use many semiconductor lasers and fibre amplifiers in which optical isolators are employed to make the light carrying our phone call or data information travel in only one direction.”

Currently, all optical isolators are made with magnets, which are bulky in size, and more importantly, cannot be integrated with other components such as lasers and optical amplifiers, like those used in communications systems.

This study, which involved researchers from University of Sydney, Tianjin Polytechnic University (China), Stanford University (USA), California Institute of Technology (USA) as well as UOW, paves the way to develop new nonmagnetic on-chip optical isolators that would potentially offer better integration with other optical components, high performances and low costs and lead to next-generation optical communications networks and large-scale arrayed beam forming systems in defence.