Researchers at the University of Sydney Nano Institute have invented a compact silicon semi­conductor chip that integrates electronics with photonic components. The new technology signi­ficantly expands radio-frequency (RF) bandwidth and the ability to accurately control information flowing through the unit. Expanded bandwidth means more information can flow through the chip and the inclusion of photonics allows for advanced filter controls, creating a versatile new semi­conductor device.

Researchers expect the chip will have appli­cation in advanced radar, satellite systems, wireless networks and the roll-out of 6G and 7G telecommuni­cations and also open the door to advanced sovereign manu­facturing. It could also assist in the creation of high-tech value-add factories at places like Western Sydney’s Aero­tropolis precinct. The chip is built using an emerging technology in silicon photonics that allows integration of diverse systems on semi­conductors less than 5 millimeters wide. Ben Eggleton, who guides the research team, likened it to fitting together Lego building blocks, where new materials are integrated through advanced packaging of components, using electronic ‘chiplets’.

Alvaro Casas Bedoya, who led the chip design, said the unique method of hetero­genous materials integration has been 10 years in the making. “The combined use of overseas semiconductor foundries to make the basic chip wafer with local research infra­structure and manu­facturing has been vital in developing this photonic integrated circuit,” he said. “This architecture means Australia could develop its own sovereign chip manu­facturing without exclusively relying on international foundries for the value-add process.”

Eggleton said the invention means the work at Sydney Nano fits well with ini­tiatives like the Semi­conductor Sector Service Bureau (S3B), sponsored by the NSW Government, which aims to develop the local semiconductor ecosystem. Nadia Court, Director of S3B, said, “This work aligns with our mission to drive advancements in semiconductor technology, holding great promise for the future of semi­conductor innovation in Australia. The result reinforces local strength in research and design at a pivotal time of increased global focus and investment in the sector.”

Designed in colla­boration with scientists at the Australian National University, the integrated circuit was built at the Core Research Facility cleanroom at the University of Sydney Nano­science Hub, a purpose-built $150 million building with advanced lithography and deposition facilities. The photonic circuit in the chip means a device with an impressive 15 gigahertz bandwidth of tunable frequencies with spectral resolution down to just 37 megahertz, which is less than a quarter of one percent of the total bandwidth. Eggleton said: “Led by our impressive PhD student Matthew Garrett, this invention is a significant advance for microwave photonics and integrated photonics research. Microwave photonic filters play a crucial role in modern communication and radar applications, offering the flexibility to precisely filter different frequencies, reducing electro­magnetic interference and enhancing signal quality.”

“Our innovative approach of integrating advanced func­tionalities into semi­conductor chips, particularly the heterogenous integration of chalco­genide glass with silicon, holds the potential to reshape the local semiconductor landscape”, Eggleton added. Senior Research Fellow Moritz Merklein said: “This work paves the way for a new generation of compact, high-resolution RF photonic filters with wideband frequency tunability, particularly beneficial in air and spaceborne RF communi­cation payloads, opening possibilities for enhanced communi­cations and sensing capa­bilities.” (Source: U. Sydney)

Reference: M. Garrett et al.: Integrated microwave photonic notch filter using a heterogeneously integrated Brillouin and active-silicon photonic circuit, Nat. Commun. 14, 7544 (2023); DOI: 10.1038/s41467-023-43404-x

Link: Institute of Photonics and Optical Science (IPOS), School of Physics, The University of Sydney, Sydney, Australia