The chip that makes calculations with light

The chip that makes calculations with light
by Robert Schreiber
Berlin, Germany (SPX) Nov 30, 2023

In a significant advancement for the field of optical wireless communication, a collaborative study involving Politecnico di Milano, Scuola Superiore Sant'Anna in Pisa, the University of Glasgow, and Stanford University has led to the creation of innovative photonic chips. These chips, capable of calculating the optimal shape of light for transmission through various environments, were detailed in a recent publication in the prestigious journal, Nature Photonics.

The challenge addressed by this research is the sensitivity of light to obstructions, even minuscule ones. Similar to how a frosted window or foggy glasses distort our vision, obstacles in optical wireless systems can severely disrupt data-carrying light beams. The information, though still present, becomes highly distorted and challenging to recover.

The breakthrough lies in the development of small silicon chips that function as intelligent transceivers. They autonomously determine the necessary shape for a light beam to efficiently traverse any given environment. These chips, by generating multiple, non-interfering overlapping beams, significantly enhance transmission capacity. This feature is crucial for meeting the demands of next-generation wireless systems.

Francesco Morichetti, Head of the Photonic Devices Lab at Politecnico di Milano, explains the core functionality of these chips. "Our chips are mathematical processors that perform calculations with light quickly and with minimal energy consumption. The optical beams are generated through basic algebraic operations, like sums and multiplications, directly on the light signals. These are then transmitted by micro-antennas integrated on the chips. This technology offers several benefits, including straightforward processing, high energy efficiency, and an enormous bandwidth exceeding 5000 GHz."

Andrea Melloni, Director of Polifab at Politecnico di Milano, highlights the growing interest in returning to analogue technologies. In the era of digital information, analogue co-processors emerge as crucial enablers for future 5G and 6G wireless interconnection systems. "Our chips work in a similar fashion, effectively bridging the gap between digital and analogue realms," Melloni adds.

Marc Sorel, Professor of Electronics at the TeCIP Institute of Scuola Superiore Sant'Anna, further elaborates on the wide-ranging applications of these optical processors. They are pivotal in various fields including neuromorphic systems, high-performance computing (HPC), artificial intelligence, quantum computing, cryptography, advanced localization, positioning, sensor systems, and in general, any system requiring rapid processing of large data volumes.

The research is part of the RESTART program, co-funded under the NRRP, focusing on 'RESearch and innovation on future Telecommunications systems and networks, to make Italy more smart'. Within RESTART, Prof. Andrea Melloni and Prof. Piero Castaldi, from the Istituto TeCIP of Scuola Superiore Sant'Anna Pisa, are leading the 'HePIC' focused project and 'Rigoletto' structural project. These initiatives aim to develop next-generation photonic integrated circuits and optical transport networks, underpinning the infrastructure for future 6G technology.

Research Report:Determining the optimal communication channels of arbitrary optical systems using integrated photonic processors