Lightmatter Debuts Bidirectional Optical Module to Slash AI Cabling

The Passage L20 CPX module utilizes bidirectional technology to transmit and receive data over a single fiber by assigning distinct wavelengths to each direction. In a standard 512-GPU scale-up pod, this architecture reduces the fiber count from roughly 130,000 to 65,000, while simultaneously eliminating 16,000 connectors. According to Lightmatter, this reduction cuts total interconnect costs by 15 percent and simplifies maintenance by lowering the number of potential failure points in the network.

By joining the Open CPX MSA, Lightmatter aligns with industry efforts to standardize near-package optics (NPO) form factors. The module delivers 6.4 terabits per second of bandwidth in a single socketed unit, placed directly adjacent to host GPUs or switches to bypass traditional faceplate density caps. The system supports 212.5 Gbps PAM4 line rates and operates over single-mode fiber at distances exceeding 500 meters. Evaluation kits for the Passage L20 CPX are scheduled to reach customers in the first quarter of 2027.