Computers that learn could become reality thanks to novel optical fibres

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Computers that function like the human brain could soon become a reality thanks to a project carried out by scientists from the UK and Singapore. The research, published in Advanced Optical Materials, has the potential to allow faster and smarter optical computers capable of learning and evolving.

The project was conducted within The Photonics Institute (TPI), a recently established dual institute between from the University of Southampton’s Optoelectronics Research Centre (ORC) in the UK, and the Nanyang Technological University’s (NTU) Centre for Disruptive Photonic Technologies in Singapore.

By using fibre made from a glass which is sensitive to light − known as chalcogenide − the researchers were able to reproduce a range of optical equivalents of brain functions. 

To simulate a nerve firing, for example, the collaborative team first had to mimick a neural resting state − the state before a neuron receives a signal − and then demonstrate the changes in electrical activity in the nerve cell as it was stimulated.

The changing properties of the chalcogenides fibres allow it to perform in the same way as the varying electrical activity in the nerve cell, with the light providing the stimulus to change these properties. This enables switching of a light signal; equivalent to a nerve cell firing.

‘Since the dawn of the computer age, scientists have sought ways to mimic the behaviour of the human brain, replacing neurons and our nervous system with electronic switches and memory,’ explained co-author Professor Dan Hewak from the ORC. ‘Now instead of electrons, light and optical fibres also show promise in achieving a brain-like computer. The cognitive functionality of central neurons underlies the adaptable nature and information processing capability of our brains.’

In the last decade, neuromorphic computing research has advanced software and electronic hardware that mimic brain functions and signal protocols, aimed at improving the efficiency and adaptability of conventional computers.

However, compared to our biological systems, today’s computers are more than a million times less efficient. Simulating five seconds of brain activity takes 500 seconds and needs 1.4MW of power, compared to the small number of calories burned by the human brain.

Using conventional fibre drawing techniques, microfibers can be produced from chalcogenide that possess a variety of broadband photoinduced effects, which allow the fibres to be switched on and off. This optical switching can be exploited for a variety of next generation computing applications capable of processing vast amounts of data in a much more energy-efficient manner.

‘By going back to biological systems for inspiration and using mass-manufacturable photonic platforms, such as chalcogenide fibres, we can start to improve the speed and efficiency of conventional computing architectures, while introducing adaptability and learning into the next generation of devices,’ said Dr Behrad Gholipour, also a co-author.

The research paves the way for scalable brain-like computing systems that enable ‘photonic neurons’ with ultrafast signal transmission speeds, higher bandwidth and lower power consumption than their biological and electronic counterparts.

‘This work implies that "cognitive" photonic devices and networks can be effectively used to develop non-Boolean computing and decision-making paradigms that mimic brain functionalities and signal protocols, to overcome bandwidth and power bottlenecks of traditional data processing,' Professor Cesare Soci said.

Further information

University of Southampton ORC

NTU Centre for Disruptive Photonics Technologies