The world’s first all-optical on-chip memory that can store data for decades, even without access to power, has been developed, potentially paving the way for optical computers.
The memory, developed by a team from the Karlsruhe Institute of Technology (KIT) and the universities of Münster, Oxford and Exeter can even store information in multiple states, not just the usual ones and zeros.
Described in the latest issue of the journal Nature Photonics, the technology is based on the so-called phase-change materials that can switch between regular crystalline and irregular amorphous states within a very short period of time. By switching between the two states, the material also changes its optical properties.
“Optical bits can be written at frequencies of up to a gigahertz,” explained Professor Wolfram Pernice from the University of Münster. “This allows for extremely quick data storage by our all-photonic memory.”
The switch from the crystalline to the amorphous state is associated with storing data, while going from amorphous to crystalline erases the stored information. Very short light pulses initiate the switch.
“The memory is compatible not only with conventional optical fibre data transmission, but also with latest processors,” Professor Harish Bhaskaran of Oxford University added.
The memory can store many bits of data in a single cell of a billionth of a metre in size and even perform autonomous calculations.
Permanent all-optical on-chip memories could considerably increase the future performance of computers and reduce their energy consumption. Together with all-optical connections, they might reduce latencies and do away with the energy-intensive conversion of optical signals into electronic signals, which is needed today when data travelling through optical fibres reaches the computers that are meant to process it.
Being able to store and process data in a purely optical manner would solve the problem.