Lightmatter announces the first 16 wavelength bidirectional link on single-mode fiber

Lightmatter, a Boston-based startup developing silicon photonics hardware aimed at AI and high-performance computing, has announced a 16-wavelength bidirectional Dense Wavelength Division Multiplexing optical link operating on one strand of standard single-mode (SM) fiber.

Powered by Lightmatter’s Passage interconnect and Guide laser technologies, this development “shatters previous limitations in fiber bandwidth density and spectral utilization and sets a new benchmark for high-performance, resilient data center interconnects,” the company stated.

Lightmatter’s Passage platform

The Lightmatter announcement continues, “With the rise of complex trillion-parameter Mixture of Experts models, scaling AI workloads is increasingly bottlenecked by bandwidth and radix (I/O port count) limitations in data center infrastructure.” Passage technology delivers 800 Gbps bidirectional bandwidth per SM fiber over several hundred meters.

While commercial bidirectional transmission on a single fiber has been limited mainly to two wavelengths, achieving 16 wavelengths has required multiple or specialized fibers. Lightmatter states that its achievement “addresses significant technical challenges related to managing complex wavelength-dependent propagation characteristics, power budget constraints, optical nonlinearity, and mitigating crosstalk and backscattering in a single fiber.”

How it works

The development incorporates a proprietary closed-loop digital stabilization system that actively compensates for thermal drift, ensuring continuous, low-error transmission over wide temperature fluctuations.

Architectural innovations make the Passage 3D CPO platform (pictured, above) inherently polarization-insensitive, maintaining robust performance even when the fibers are being handled or subject to mechanical stress. Standard SM fiber, while offering immense bandwidth potential, does not inherently maintain light’s polarization state, unlike specialized and more costly polarization-maintaining fiber.

This combination of unparalleled fiber bandwidth density, efficient spectral utilization, and robust performance makes Lightmatter's Passage technology foundational for the industry’s transition from electrical to optical interconnects in AI data centers. It empowers customers to accelerate development of larger and more capable AI models with more powerful, efficient, and scalable data centers.

‘Architectural leap’

Nicholas Harris, founder and CEO, commented, “Data centers are the new unit of compute in the AI era, with the next 1000X performance gain coming largely from ultra-fast photonic interconnects. Our 16-lambda bidirectional link is an architectural leap forward. Hyperscalers can achieve significantly higher bandwidth density with standard single-mode fiber, reducing both capital expenditure and operational complexity, while enabling higher radix — more connections per XPU or switch,” said Harris.

Alan Weckel, co-founder and analyst at market intelligence group 650 Group, said, “Lightmatter’s ability to dramatically increase bandwidth density on existing single-mode fiber, coupled with the technology’s robust thermal performance, is a game-changer for data center scalability and efficiency. This solves one of the most pressing challenges in AI development.”

Source: optics.org