Lightmatter Achieves 16-Wavelength Bidirectional Link on Single-Mode Optical Fiber
Photonic supercomputing company Lightmatter has achieved a 16-wavelength bidirectional dense wavelength division multiplexing (DWDM) optical link operating on one strand of standard single-mode fiber. According to Lightmatter, the advance overcomes previous limitations in fiber bandwidth density and spectral utilization.
As AI increases in complexity, bottlenecks in bandwidth and radix (I/O port count) become more apparent. Lightmatter’s Passage interconnect technology provides 800 Gbps bidirectional bandwidth (400 Gbps transmit and 400 Gbps receive) per single-mode fiber for distances of several hundred meters or more. The technology advances chip I/O design by simultaneously increasing both radix and bandwidth per fiber compared to existing co-packaged optics (CPO) solutions.
While commercial bidirectional transmission on a single fiber has been limited mainly to two wavelengths, achieving 16 wavelengths has, historically, required multiple or specialized fibers. The advancement by Lightmatter addresses the technical challenges related to managing complex wavelength-dependent propagation characteristics, power budget constraints, optical nonlinearity, and mitigating crosstalk and backscattering in a single fiber. Such innovations, the company said, pave the way for the next major advances in AI model development, which demand more extensive and efficient high-bandwidth networking than exists today.
“Data centers are the new unit of compute in the AI era, with the next 1000× performance gain coming largely from ultra-fast photonic interconnects,” said Nicholas Harris, founder and CEO of Lightmatter. “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.”
Lightmatter's solution incorporates a proprietary closed-loop digital stabilization system that actively compensates for thermal drift, ensuring continuous, low-error transmission over wide temperature fluctuations. In addition, architectural innovations make the Passage 3D CPO platform inherently polarization-insensitive, maintaining robust performance even when the fibers are being handled or subject to mechanical stress. Standard single-mode fiber, while offering immense bandwidth potential, does not inherently maintain light's polarization state, unlike specialized and more costly polarization-maintaining fiber. Achieving polarization insensitivity allows the company to use cost-effective single-mode fiber for its bidirectional DWDM technology.
For Lightmatter, the development comes 10 months after the company's $400 million funding round.
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