Lightmatter Introduces 12.8 Tbps Bidirectional Optical Module

Lightmatter announced in a press release that it joined the Open CPX Multi Source Agreement and introduced the Passage L20 CPX. The company describes it as the first Open CPX module for AI infrastructure to combine transmission and reception over one fiber.

The module provides 12.8 Tbps of total bandwidth, split between 6.4 Tbps for transmission and 6.4 Tbps for reception. It uses 32 optical lanes in each direction at a 212.5 Gbps PAM4 line rate and supports distances beyond 500 meters over single mode fiber.

Lightmatter estimates that the module could reduce fiber use in a 512 GPU scale up pod from about 130,000 fibers to 65,000. It could also remove about 16,000 connectors and lower scale up interconnect network costs by roughly 15 percent.

The Passage L20 CPX supports 1331 nm and 1311 nm O band wavelengths and can pair with the Guide DR laser module or compatible external laser sources. Evaluation kits are expected to ship in the first quarter of 2027. Its specifications and performance figures remain preliminary.