IBM Research has unveiled a significant advancement in optical interconnect technology for advanced data center communications. The breakthrough centers on a novel co-packaged optics (CPO) system featuring a sophisticated Polymer Optical Waveguide (PWG) design, marking a potential shift from traditional copper-based interconnects. The innovation introduces a Photonic Integrated Circuit (PIC) measuring 8x10mm, mounted on a 17x17mm substrate, capable of converting electrical signals to optical ones and vice versa. The system's waveguide, spanning 12 mm in width, efficiently channels light waves through precisely engineered pathways, with channels converging from 250 to 50 micrometers.

While current copper-based solutions like NVIDIA's NVLink offer impressive 1.8 TB/s bandwidth rates, and Intel's Optical Compute Interconnect achieves 4 TBit/s bidirectional throughput, IBM's technology focuses on scalability and efficiency. The company plans to implement 12 carrier waves initially, with the potential to accommodate up to 32 waves by reducing spacing to 18 micrometers. Furthermore, the design allows for vertical stacking of up to four PWGs, potentially enabling 128 transmission channels. The technology has undergone rigorous JEDEC-standard testing, including 1,000 cycles of thermal stress between -40°C and 125°C, and extended exposure to extreme conditions including 85% humidity at 85°C. The components have also proven reliable during thousand-hour storage tests at various temperature extremes. The bandwidth of the CPO is currently unknown, but we expect it to surpass current solutions.The new CPO technology could accelerate Large Language Model (LLM) training by up to five times, potentially reducing training periods from three months to just three weeks. The innovation also promises substantial energy efficiency improvements, with researchers claiming a more than 80% reduction in power consumption compared to conventional electrical interconnects. IBM has implemented some composition adjustments, and new testing phases are underway, with findings expected in early 2025. With the JEDEC level of testing, IBM could push CPO to become a JEDEC standard in 2025.