Seoul researchers propose programmable photonic chip that can slow light on demand

Researchers from Seoul National University and the University of Seoul designed a programmable photonic integrated circuit that can slow, delay, and control light when needed, SciTechDaily reported. The work, led by Professors Namkyoo Park and Sunkyu Yu with Professor Xianji Piao, was published in Advanced Science. Conventional electronic semiconductors face heavy power use and limited data transfer speeds as generative AI demand grows, driving interest in optical computing. Fixed optical delay hardware based on coupled-resonator-induced transparency is often locked after fabrication, making buffers and synchronization hard to reconfigure for data centers and AI servers. The team treated bright and dark optical modes as one design parameter and added two adjustable loop couplers so resonator structures can be reconfigured after fabrication. Theoretical analysis and numerical simulations indicated the couplers could control passband width and shape, delay, and transmission, including dynamic changes to optical pulse speed without sacrificing processing performance. Three-dimensional electromagnetic simulations suggested the design could be built on a silicon nitride photonic platform and remain reliable under realistic losses, phase errors, and thermal crosstalk. Co-corresponding author Namkyoo Park said the design principle lets the flow of light in photonic circuits be reconfigured as needed and that the group plans to expand toward large-scale programmable silicon photonics and photonic AI technologies. Co-first authors Seungkyun Park and Beomjoon Chae said they plan further work toward practical device implementation and experimental validation. Reference DOI: 10.1002/advs.76378.