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OFC 2026: Broadcom and Coherent photonic interconnect specs

Simple Tech Trend (OFC Panel Report) USA
Overview
An OFC 2026 panel highlighted the critical challenge of ultra-low-power photonic scale-up interconnects for AI clusters, showcasing diverse technological approaches. Broadcom demonstrated approximately 1 pJ/bit with its VCSEL Near-Package Optics (NPO) solution, while Coherent achieved an impressive 0.18 pJ/bit of core optoelectronic energy. Marvell presented a more comprehensive silicon photonics Co-Packaged Optics (CPO) solution with analog DSP, delivering 3 pJ/bit for the total link via WDM, signaling an intense race to optimize power efficiency and bandwidth for next-generation AI infrastructure.
In Depth

Key Findings

At the OFC 2026 panel, leading industry players presented their latest advancements in achieving ultra-low-power photonic scale-up interconnects, a critical requirement for next-generation AI data centers. Broadcom’s VCSEL Near-Package Optics (NPO) solution attained approximately 1 pJ/bit, while Coherent demonstrated an even lower 0.18 pJ/bit of core optoelectronic energy, setting new benchmarks for efficiency. Marvell’s silicon photonics Co-Packaged Optics (CPO) approach, integrating analog DSP, achieved 3 pJ/bit for the total link, providing a more complete solution for bandwidth scaling through WDM.

Technical Details

  • Broadcom’s VCSEL NPO: Broadcom’s strategy focuses on 100G/200G VCSELs due to their cost-effectiveness and manufacturability. Their NPO implementation delivered an energy efficiency of approximately 1 pJ/bit, positioning VCSELs as a strong contender for raw power efficiency in certain applications.
  • Coherent’s Optoelectronic Energy: Coherent showcased a remarkable 0.18 pJ/bit in core optoelectronic energy. This figure represents the energy consumption within the core optical-to-electrical conversion components, indicating highly optimized device-level performance.
  • Marvell’s Silicon Photonics CPO: Marvell’s solution leverages silicon photonics with external lasers and analog DSP, offering a scalable approach via WDM. While its total link energy consumption was 3 pJ/bit, this includes the full link budget, providing a practical solution for deploying high-bandwidth AI clusters, particularly post-2027.
  • NVIDIA’s Direction: NVIDIA is also actively pursuing high-bandwidth-density silicon photonics CPO with external lasers and analog DSP for its top-tier AI clusters, aligning with Marvell’s vision for future AI networking architectures.

Background & Context

The explosive growth of AI workloads demands unprecedented bandwidth and ultra-low power consumption for interconnects within data centers. As AI clusters scale to thousands of accelerators, even marginal improvements in pJ/bit energy efficiency can translate into significant operational cost savings and reduced environmental impact. The discussion at OFC 2026 highlighted a divergence in technological roadmaps, with some favoring VCSELs for their established manufacturing and cost advantages, while others champion silicon photonics CPO for its integration density and scalability for advanced AI fabrics. The evolving AI infrastructure increasingly seeks open, multi-vendor Scale-Up fabrics, creating a layered coexistence model where proprietary and open Ethernet-based technologies compete and complement each other.

Strategic Significance & Outlook

The panel discussion underscores the intense innovation in photonic interconnects, driven by the insatiable demands of AI. The competing technologies—VCSEL-based NPO versus silicon photonics CPO with external lasers and analog DSP—each offer distinct advantages. VCSELs excel in raw power efficiency and cost for shorter reaches, while silicon photonics CPO promises higher integration density and bandwidth for larger, more complex AI clusters. The industry is moving towards a future where hybrid solutions and application-specific optimizations will likely dictate market adoption. The continuous push for sub-1 pJ/bit interconnects will be pivotal in enabling the next generation of AI supercomputers, impacting everything from data center design to sustainable computing practices.

Source: https://www.simpletechtrend.com/en/post/ofc2026-ai-scale-up-cpo-vcsel-photonics-analysis-en

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