Lightmatter introduced the Passage L20 optical engine, a 6.4 Tbps (per direction) photonic module designed to accelerate deployment of high-bandwidth optical interconnects for next-generation AI data centers. The new platform targets Near-Packaged Optics (NPO) and On-Board Optics (OBO) applications and uses bidirectional (BiDi) optical transmission to increase fiber bandwidth density while reducing cabling complexity.
The Passage L20 extends Lightmatter’s Passage photonic interconnect portfolio and supports emerging AI cluster architectures where electrical signaling and traditional pluggable optics struggle to keep pace with bandwidth and reach requirements. With next-generation switches expected to exceed 100 Tbps of throughput and more than 576 ports, optical connectivity must deliver higher density while simplifying rack-scale cabling. The Passage L20 addresses this requirement by enabling BiDi multiplexing across shared fibers, reducing fiber requirements by up to 50% compared with traditional unidirectional data-center-reach optical standards.
The module supports IEEE 802.3dj-compliant 224G PAM4 electrical interfaces, enabling drop-in integration with existing XPU and switch packages. Lightmatter positions the L20 as a bridge between conventional pluggable optics and more advanced 3D co-packaged photonic engines, allowing hyperscalers and system designers to deploy optical interconnects within current chassis architectures while preparing for future photonic integration.
| Parameter | Specification |
| Total Bandwidth | 6.4 Tbps per direction |
| Electrical Interface | 224G PAM4 (IEEE 802.3dj compliant) |
| SerDes Line Rate | 212.5 Gbps PAM4 |
| Optical Transmission | 2-wavelength BiDi (1311 nm / 1331 nm), DR compatible |
| Optical Ports | 32 ports at 200 Gbps per lane |
| Thermal Design Power | 30 W max (~3.0 pJ/bit) |
| Form Factor | 2000-pin BGA optical engine module |
| Availability | Sampling expected late 2026 |
The Passage L20 supports multiple integration strategies. In Near-Packaged Optics (NPO) configurations, the module can sit adjacent to an ASIC on the main PCB or on a mezzanine board. In On-Board Optics (OBO) deployments, the module can mount directly on the PCB edge with optional retimers depending on channel reach. Each module provides 32 optical ports operating at 200 Gbps per lane data rates to support high-density interconnect topologies including XPU-to-XPU clusters, XPU-to-switch scale-up networks, and hierarchical switch fabrics.
“The demand for our photonic technology is expanding rapidly across a wide range of AI applications that require immediate, large-scale deployment,” said Nick Harris, Ph.D., founder and CEO of Lightmatter. “With the introduction of the Passage L20 optical engine, we are offering a versatile, standards-based platform that complements our advanced 3D-integrated roadmap.”
🌐 Analysis: Optical interconnect architectures are evolving quickly as hyperscalers push AI cluster scale into tens of thousands of accelerators. NPO and OBO approaches allow optical engines to move closer to compute and switching silicon without requiring full co-packaged optics, offering a pragmatic step toward photonic integration. Lightmatter’s strategy of offering multiple integration paths reflects broader industry experimentation across pluggables, linear optics, near-package optics, and full CPO architectures as vendors seek the most practical path to scale AI fabrics.
