With trillion-parameter Mixture of Experts (MoE) 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 (400 Gbps transmit and 400 Gbps receive) per single-mode fibre for distances of several hundred metres or more.
This achievement advances chip I/O design by simultaneously increasing both radix and bandwidth per fibre compared to existing co-packaged optics (CPO) solutions.
While commercial bidirectional (BiDi) transmission on a single fibre has been limited mainly to two wavelengths, achieving 16 wavelengths has historically required multiple or specialised fibres.
This development 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 fibre. .
The technology incorporates a proprietary closed-loop digital stabilisation system that actively compensates for thermal drift, ensuring continuous, low-error transmission over wide temperature fluctuations.
Architectural innovations make the Passage 3D CPO platform inherently polarisation-insensitive, maintaining robust performance even when the fibres are being handled or subject to mechanical stress.
Standard SM fibre, while offering immense bandwidth potential, does not inherently maintain light’s polarisation state, unlike specialised and more costly polarisation-maintaining (PM) fiber. Achieving polarisation insensitivity allows the use of cost-effective SM fibre for its bidirectional DWDM technology.
Lightmatter has raised $850 million. Its latest funding round last October – its Series D – raised $400 million at a valuation of $4.4 billion.
For more: https://lightmatter.co/.
