The National Institute of Information and Communications Technology (NICT), together with 11 international research partners, has demonstrated a record-breaking 430 terabits per second (Tb/s) optical transmission using a novel approach that extends the capacity of standard-compliant cutoff-shifted optical fibers well beyond the original design.

The technology introduces a novel method that multiplies the usable capacity of certain spectral regions by up to three times. This approach exploits the properties of standard-compliant cutoff-shifted optical fibers based on the ITU-T G.654 recommendation, which have been originally designed to operate with light at relatively long wavelengths, in the C and L bands of transmission bands. By using light with shorter wavelengths, in the O-band region, researchers were able to realize three-mode transmission instead of the traditional single-mode transmission. This effectively extended the optical fiber capacity well beyond the intended design by combining single-mode transmission in the E/S/C/L bands with three-mode transmission in the O band. The team achieved a new optical transmission record of 430 Tb/s in international-standard-compliant optical fibers, surpassing the previous our record of 402 Tb/s, which was also set in 2024. Remarkably, the new result was obtained using nearly 20% less overall bandwidth, resulting in a simpler system that demonstrates how existing infrastructure can be pushed even further without costly upgrades.

The new technology builds on standard-compliant cutoff-shifted optical fiber technology and has the potential to be applied to metropolitan area networks and inter-datacenter links, where high-capacity connections are increasingly in demand, and standard-compliant cutoff-shifted optical fibers are already installed. The combination of high throughput, reduced complexity, and compatibility with existing infrastructure points to a more scalable and energy-efficient future for optical communications.

This achievement was reported as a post deadline paper at the 51st European Conference on Optical Communication (ECOC) 2025 on Thursday Oct. 2, 2025, at the Bella Center, Copenhagen, Denmark, and was partly supported by the Japan-Germany Beyond 5G/6G collaboration initiative.

As the C language, which forms the basis of critical global software like operating systems, faces security limitations, KAIST's research team is pioneering core original technology research for the accurate automatic conversion to Rust to replace it. By proving the mathematical correctness of the conversion, a limitation of existing Artificial Intelligence (LLM) methods, and solving C language security issues through automatic conversion to Rust, they presented a new direction and vision for future software security research. This work has been selected as the cover story for CACM, the world's highest-authority academic journal, thereby demonstrating KAIST's global research leadership in the field of computer science.

Photon avalanche (PA) upconversion, driven by a positive feedback loop that couples nonresonant ground-state absorption (GSA), resonant excited-state absorption (ESA), and highly efficient cross-relaxation (CR), gives rise to a threshold-triggered ultrahigh optical nonlinearity accompanied by uniquely prolonged rise-time dynamics. From spark to surge, this phenomenon can deliver tens to even hundreds of nonlinear orders at the nanoscale, redefining opportunities in imaging, sensing, and optical computing while opening a new paradigm for interrogating light–matter interactions.

Researchers have developed an eco-friendly method to create gold nanoparticles (AuNPs) using microalgae. This "green synthesis" avoids harsh chemicals, resulting in nanoparticles that are more stable than conventional ones. When activated by a laser, these AuNPs effectively destroy cancer cells while showing lower toxicity to healthy cells. This breakthrough promises a more sustainable and safer approach to photothermal cancer therapy and other applications in nanomedicine.

NIMS has been developing chemical sensors as a key component of the artificial olfaction technology (olfactory sensors), with the aim of putting this technology into practical use. In this study, explainable AI (XAI) was used to reveal how chemical sensors discriminate among various odorant molecules. The findings may help guide the selection of receptor materials for developing high-performance chemical sensors capable of detecting odorant molecules. The achievement is expected not only to improve the performance of artificial olfaction but also to advance understanding of human olfactory mechanisms. This research was published online in ACS Applied Materials & Interfaces on September 9, 2025.