Key innovation in photonic components could transform supercomputing technology

Programmable photonic integrated circuits (PPICs) process light waves for computing, sensing, and signaling so that they can be programmed to meet various requirements. Researchers from the Daegu Gyeongbuk Institute of Science and Technology (DGIST), South Korea, in collaboration with collaborators from the Korea Advanced Institute of Science and Technology (KAIST), have made a major breakthrough in integration of microelectromechanical systems in PPICs.

Their research was published in the journal Natural photonics.

“Programmable photonic processors promise to outperform conventional supercomputers, providing faster, more efficient, and massively parallel computing capabilities,” says Sangyoon Han of the DGIST team. He points out that in addition to the increased speeds achieved by using light instead of electric current, the significant reduction in power consumption and size of PPICs could lead to major advances in the fields of artificial intelligence, neural networks, quantum computing and communications.

Microelectromechanical systems (MEMS) at the heart of this new advancement are tiny components capable of converting optical, electronic and mechanical changes to perform the variety of communications and mechanical functions necessary for an integrated circuit.

The researchers believe they are the first to integrate silicon-based photonic MEMS technologies onto PPIC chips that operate with extremely low power requirements.

“Our innovation has significantly reduced power consumption to femtowatt levels, which represents a million-fold improvement over the previous state of the art,” says Han. The technology can also be integrated into chips up to five times smaller than existing options.

One of the keys to dramatically reducing energy requirements was moving away from the reliance on temperature changes required by the dominant “thermo-optical” systems currently in use. The tiny mechanical movements required are powered by electrostatic forces – the attractions and repulsions between fluctuating electrical charges.

Components built into the team’s chips can manipulate a characteristic of light waves called “phase” and control the coupling between different parallel waveguides, which guide and constrain the light. These are the two most fundamental requirements for creating PPIC. These features interact with micromechanical “actuators” (essentially switches) to complete the programmable integrated circuit.

The key to progress has been applying innovative concepts to manufacturing the required silicon-based parts. Importantly, the manufacturing process can be used with conventional silicon wafer technology. This makes it compatible with large-scale production of photonic chips essential for commercial applications.

The team now plans to refine its technology to build and commercialize a photonic computer that will outperform conventional electronic computers in a wide variety of applications. Han says examples of specific uses include crucial inference tasks in artificial intelligence, advanced image processing and high-bandwidth data transmission.

“We plan to continue pushing the boundaries of computing technology, contributing further to the field of photonics and its practical applications in modern technology,” concludes Han.