Optical computing components from phase change materials
New and exciting approaches and architecture designs are transforming the world of computing. Photonic computing represents a solution with a plethora of advantages over traditional semiconductor systems. Amongst the advantages of using all-optical systems are higher transmission speeds, lower energy consumption and systems miniaturization. Widespread implementation of photonic computing requires the development of efficient optical transistors and non-volatile optical memory.
Researchers at the University of Oxford have developed micro-optical switches and all-photonic memory based on phase change materials (PCM) for optical communications and computing. The microscale tuneable switches can be electrically or optically controlled showing ultrafast switching times and low energy consumption. Besides, they can work in a very large wavelength range. The photonic memory is non-volatile and multi-level with low switching energies and high readout speeds.
Our information age depends on electronic devices, which exploit the flow of electrons to transmit information. However, increasing pressure to improve the speed and storage capacity of new devices has led to the quest for different methodologies. In this context, optical devices represent an attractive alternative for the management of information. It has been proposed that by using photons for computation, instead of electrons, higher bandwidth devices could be developed.
In order to avoid energy losses encountered in electronic to optical conversion, a fully optical device is desirable. To achieve this goal, optical equivalents of current computer components are required. Two key components of a modern semiconductor based computer are memory and CPU. Current optical memory solutions are typically volatile, meaning that they maintain data only when powered. Optical switches for use in photonic CPUs have, at present, not been miniaturised sufficiently. Research at the University of Oxford has produced optical computer components based on superlattice phase change materials (PCMs) that overcome many of the limitations of current components.
The changing phase of optical computing
These new devices use PCMs to modulate the transmission of light. The reversible changes between the amorphous and crystalline state of PCMs, induced by electrical or optical stimuli, provoke changes in the way light is transmitted. Their integration in all-photonic or electro-optical platforms (combination of electronic and optical devices) allows their use in optical routers, optical gates and in non-volatile and multi-level storage.
We believe the key advantages of the Oxford technology to be:
- Ultrafast and reversible switching
- Low energy consumption
- Ultra-small size
- Very large working wavelength range
- Easy integration in photonic or electro-optic platforms
A number of patent applications directed to the technology have been filed and Oxford University Innovation is actively seeking commercial partners to develop the technology further.
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