{"slug": "inside-the-copper-to-optics-shift-in-ai-data-centers", "title": "Inside the Copper-to-Optics Shift in AI Data Centers", "summary": "Broadcom's Tomahawk 6 switch family is shipping in production volume, while its Davisson co-packaged-optics variant is available to early customers, though Broadcom has not publicly quantified CPO production volumes or named a deployment. Nvidia and Cisco target broader system availability for 1.6T optical products during the second half of 2026, and Lightmatter's L20 optical engine is due to begin sampling late in the year. The transition from copper to optics in AI data centers is driven by copper's diminishing reach at higher signaling rates, with OIF's roadmap showing long-reach copper objectives falling from three meters at 56G to one meter at 224G per lane.", "body_md": "# Inside the Copper-to-Optics Shift in AI Data Centers\n\n- Broadcom’s conventional Tomahawk 6 switch family is shipping in production volume. Its Davisson co-packaged-optics variant is available to early customers, but Broadcom has not publicly quantified CPO production volumes or named a deployment.\n[[1]](https://www.broadcom.com/company/news/product-releases/64031)[[2]](https://www.broadcom.com/company/news/product-releases/63626) - Supplier roadmaps show 800G pluggable transceivers continuing to ramp as 1.6T products enter the market. Nvidia and Cisco are targeting broader system availability during the second half of 2026, while Lightmatter’s L20 optical engine is due to begin sampling late in the year.\n[[3]](https://www.coherent.com/content/dam/coherent/site/en/documents/investors/investor-presentations/2026/may-6/investor-presentation-20260506.pdf)[[4]](https://www.nvidia.com/en-us/networking/products/silicon-photonics/)[[5]](https://newsroom.cisco.com/c/r/newsroom/en/us/a/y2026/m02/cisco-announces-new-silicon-one-g300.html)[[6]](https://www.cisco.com/c/dam/en_us/training-events/events/engage-tech-days/2026/milwaukee/empowering-data-centers-ciscos-path-to-modernization-operational-excellence.pdf)[[7]](https://lightmatter.co/press-release/lightmatter-expands-photonic-interconnect-roadmap-with-passage-l20-unified-optical-engine-for-npo-and-obo-applications/) - Copper remains inexpensive and serviceable at short distances, but higher signaling rates reduce its practical reach and require more equalization, retiming and power.\n[[8]](https://www.oiforum.com/wp-content/uploads/OIF-FD-CEI-448G-01.0.pdf) - The new OCI specification gives AMD, Broadcom, Meta, Microsoft, Nvidia and OpenAI a common optical scale-up interface. It does not replace Ethernet, UALink or other network protocols.\n[[11]](https://oci-msa.org/assets/files/200G-OCI-Optical-Phy-Specification-v1.0.pdf)\n\nOptical transceivers already connect racks and buildings throughout large data centers. The change now underway is more difficult: moving the electrical-to-optical conversion from a removable module at the front of a switch toward the switch or accelerator package itself.\n\nThe transition is real, but product status varies sharply. Broadcom’s 102.4-terabit-per-second Tomahawk 6 switch family is in production volume. Its Davisson co-packaged-optics version is further along than most integrated-optics projects, although Broadcom’s public disclosures do not establish its production volume or identify a customer deployment. Across the wider market, 800-gigabit pluggables are still ramping, 1.6-terabit modules are entering deployment, and near-package or compute-level optical I/O remains largely in sampling and validation.[[1]](https://www.broadcom.com/company/news/product-releases/64031)[[2]](https://www.broadcom.com/company/news/product-releases/63626)[[3]](https://www.coherent.com/content/dam/coherent/site/en/documents/investors/investor-presentations/2026/may-6/investor-presentation-20260506.pdf)\n\n## Why copper runs out of road\n\nCopper cables and circuit-board traces are cheap, familiar and easy to replace. They also avoid the lasers, photodetectors and fiber assembly required for an optical link. For short connections inside a server or rack, those advantages remain compelling.\n\nThe problem is that electrical signals weaken and interfere with one another as lane speeds and distances rise. OIF’s roadmap lists long-reach copper objectives falling from three meters at 56 gigabits per second per lane to two meters at 112G and one meter at 224G. The corresponding reach for its emerging 448G generation remains undetermined.[[8]](https://www.oiforum.com/wp-content/uploads/OIF-FD-CEI-448G-01.0.pdf)\n\nSystem designers can recover a deteriorating signal with better materials, equalizers, retimers and digital signal processors. Those components consume power, add latency and occupy board space. At some point, converting bits into light closer to the chip becomes attractive because fiber can carry high bandwidth farther without the same electrical loss.\n\nThat does not mean copper disappears. Passive and active copper links are likely to remain in short, cost-sensitive connections. The boundary moves inward as accelerators and switches require more bandwidth. Meta has described advanced optics as the viable path beyond the bandwidth-density and backplane constraints confronting future systems, while also acknowledging unresolved reliability and manufacturing challenges.[[9]](https://engineering.fb.com/2025/09/29/data-infrastructure/metas-infrastructure-evolution-and-the-advent-of-ai/)\n\n## From pluggables to optical I/O\n\nA conventional pluggable transceiver sits at the switch faceplate. High-speed electrical traces carry data from the switch chip across the board to the module, where optical components convert it to light. Retimed modules use a digital signal processor to restore the electrical signal. The architecture has a mature supply chain, supports field replacement and can allow operators to qualify modules from multiple vendors.\n\nLinear pluggable optics, or LPO, retain the removable module but eliminate its retiming DSP. Cisco claims its 800G LPO design cuts module power by 50% compared with retimed modules and can reduce total switch power by 30%. Those are vendor estimates, and the trade-off is a tighter electrical channel: the switch silicon, board and module must work together without the signal-restoration margin supplied by a DSP.[[5]](https://newsroom.cisco.com/c/r/newsroom/en/us/a/y2026/m02/cisco-announces-new-silicon-one-g300.html)\n\nNear-package optics and on-board optics shorten that electrical path by mounting optical engines beside the ASIC or elsewhere on the host board. Lightmatter’s Passage L20 is a 6.4-terabit-per-second bidirectional engine designed for both arrangements. It uses a 224G-class electrical interface and is expected to begin sampling in late 2026 rather than entering immediate volume production.[[7]](https://lightmatter.co/press-release/lightmatter-expands-photonic-interconnect-roadmap-with-passage-l20-unified-optical-engine-for-npo-and-obo-applications/)\n\nCo-packaged optics moves the optical engines onto the same package as a switch or accelerator. Optical I/O goes further by making photonics part of the compute package or interposer, reducing dependence on electrical connections between chips. Lightmatter’s M1000 evaluation system demonstrates 114.6 terabits per second of bidirectional bandwidth in the company’s validation data center, but it remains an evaluation platform rather than a disclosed customer production deployment.[[10]](https://lightmatter.co/products/passage-m1000-evk/)\n\n## What is actually shipping in July 2026\n\nBroadcom said in March that the Tomahawk 6 family was shipping in production volume. The family includes conventional electrical-I/O configurations as well as support for co-packaged optics.[[1]](https://www.broadcom.com/company/news/product-releases/64031)\n\nThe status of the CPO-specific Davisson version requires more care. Broadcom’s October 2025 announcement described Davisson as shipping, but the availability section of the same release said the device was being sampled to early-access customers and partners. Davisson integrates 16 optical engines providing 6.4 terabits per second each. Broadcom has since shown the system and continued to market it as a shipping CPO product, but has not publicly separated its volume from the broader Tomahawk 6 family or named an operator using it in production.[[2]](https://www.broadcom.com/company/news/product-releases/63626)\n\nPluggables have clearer deployment evidence across the supplier base. Coherent’s May roadmap described 800G modules as continuing to ramp and 1.6T products as entering an accelerated ramp during 2026. Cisco said all major hyperscalers were deploying its coherent pluggables for data-center interconnect and scale-across applications, with its 800G shipments increasing. Those coherent links serve longer data-center connections rather than replacing short-reach scale-up copper inside a rack.[[3]](https://www.coherent.com/content/dam/coherent/site/en/documents/investors/investor-presentations/2026/may-6/investor-presentation-20260506.pdf)[[12]](https://investor.cisco.com/files/doc_events/2026/02/Q2FY26-Prepared-Remarks-1.pdf)\n\nNvidia now says Spectrum-X Ethernet Photonics has reached production through its manufacturing ecosystem, while its product page still places system availability in the second half of 2026. Nvidia claims fivefold power-efficiency gains over traditional pluggable-transceiver networks, but that comparison is a company platform estimate rather than an independently measured industry baseline.[[4]](https://www.nvidia.com/en-us/networking/products/silicon-photonics/)\n\nCisco is targeting the second half of 2026 for its first G300-based systems and lists its 1.6T OSFP optics for the same period. Cisco cautions that many of the announced products remain in development and that release schedules may change.[[5]](https://newsroom.cisco.com/c/r/newsroom/en/us/a/y2026/m02/cisco-announces-new-silicon-one-g300.html)[[6]](https://www.cisco.com/c/dam/en_us/training-events/events/engage-tech-days/2026/milwaukee/empowering-data-centers-ciscos-path-to-modernization-operational-excellence.pdf)\n\nNot every 1.6T demonstration indicates the same readiness. Lumentum presented its 1.6T DR4 OSFP module with four 400G lasers as an OFC 2026 prototype and a step toward future 3.2T products.[[13]](https://www.lumentum.com/en/videos/16t-dr4-osfp-module-400g-differential-emls)\n\nLightmatter’s L20 is expected to begin sampling late in 2026. Its more integrated Passage CPO chiplets are available through evaluation kits for lead-customer testing, not disclosed volume deployment.[[7]](https://lightmatter.co/press-release/lightmatter-expands-photonic-interconnect-roadmap-with-passage-l20-unified-optical-engine-for-npo-and-obo-applications/) [15] Lightmatter CEO Nick Harris told Tom’s Hardware that he expects 2027 and 2028 to be important years for near-package optics and said the company expects more integrated CPO parts to ship in 2028.\n\n[[14]](https://www.tomshardware.com/tech-industry/inside-optical-and-the-battle-for-scale-how-the-ai-industry-is-racing-to-integrate-photonic-interconnects)## Standards cannot remove the packaging trade-offs\n\nThe Optical Compute Interconnect Multi-Source Agreement, founded by AMD, Broadcom, Meta, Microsoft, Nvidia and OpenAI, released version 1.0 of its 200G optical physical-interface specification on March 11, 2026. OCI uses non-return-to-zero signaling and wavelength-division multiplexing to define an interoperable optical interface for scale-up systems.[[11]](https://oci-msa.org/assets/files/200G-OCI-Optical-Phy-Specification-v1.0.pdf)\n\nOCI addresses how an optical engine connects at the physical layer. It does not dictate the entire network. Ethernet and Ultra Ethernet address scale-out fabrics, while NVLink and the emerging UALink ecosystem cover scale-up protocols and switching. OIF specifications cover electrical interfaces and module management, and IEEE 802.3 continues to define Ethernet physical layers. A deployable system will depend on several overlapping standards.\n\nNor does standardization eliminate the operational choices. Pluggables concentrate more electronics at the faceplate but are easy to swap. LPO reduces power while demanding tighter system engineering. Near-package optics preserves some separation between an expensive ASIC and its optical engines. CPO offers greater density and shorter electrical paths, but fiber attachment, optical testing, cooling and field repair become part of the switch or accelerator design.\n\nExternal laser sources can keep a heat-sensitive and potentially replaceable component away from the main package, but they add connectors, fiber routes and redundancy requirements. Optical suppliers must also expand production of lasers, silicon-photonics wafers and precision fiber assemblies. Coherent expects new CPO and near-package revenue in the second half of 2026, but that is a supplier forecast rather than evidence of broad hyperscaler deployment.[[3]](https://www.coherent.com/content/dam/coherent/site/en/documents/investors/investor-presentations/2026/may-6/investor-presentation-20260506.pdf)\n\nThe transition will therefore be incremental. Copper will handle the shortest links, pluggables will remain the most mature serviceable option, and integrated optics will first enter systems where bandwidth density and power justify added packaging complexity. The milestones to watch are customer availability for Nvidia and Cisco systems during the second half of 2026, Lightmatter’s L20 samples late this year, broader near-package adoption in 2027 and 2028, and named production deployments of optical I/O beside compute silicon.[[4]](https://www.nvidia.com/en-us/networking/products/silicon-photonics/)[[5]](https://newsroom.cisco.com/c/r/newsroom/en/us/a/y2026/m02/cisco-announces-new-silicon-one-g300.html)[[6]](https://www.cisco.com/c/dam/en_us/training-events/events/engage-tech-days/2026/milwaukee/empowering-data-centers-ciscos-path-to-modernization-operational-excellence.pdf)[[7]](https://lightmatter.co/press-release/lightmatter-expands-photonic-interconnect-roadmap-with-passage-l20-unified-optical-engine-for-npo-and-obo-applications/)[[14]](https://www.tomshardware.com/tech-industry/inside-optical-and-the-battle-for-scale-how-the-ai-industry-is-racing-to-integrate-photonic-interconnects)\n\n## Companies mentioned\n\n## Further sources\n\n[[1] Broadcom, “Broadcom Now Shipping World’s First 102.4 Tbps Switch in Production … ↗](https://www.broadcom.com/company/news/product-releases/64031)\n\n[[2] Broadcom, “Broadcom Announces Tomahawk 6 – Davisson, the Industry’s First 102.4… ↗](https://www.broadcom.com/company/news/product-releases/63626)\n\n[[3] Coherent, third-quarter fiscal 2026 investor presentation, including its transc… ↗](https://www.coherent.com/content/dam/coherent/site/en/documents/investors/investor-presentations/2026/may-6/investor-presentation-20260506.pdf)\n\n[[4] Nvidia, Silicon Photonics Networking product overview and Spectrum-X production… ↗](https://www.nvidia.com/en-us/networking/products/silicon-photonics/)\n\n[[5] Cisco, “Cisco Announces New Silicon One G300, Advanced Systems and Optics,” Feb… ↗](https://newsroom.cisco.com/c/r/newsroom/en/us/a/y2026/m02/cisco-announces-new-silicon-one-g300.html)\n\n[[6] Cisco, “Empowering Data Centers,” including second-half 2026 timing for its 1.6… ↗](https://www.cisco.com/c/dam/en_us/training-events/events/engage-tech-days/2026/milwaukee/empowering-data-centers-ciscos-path-to-modernization-operational-excellence.pdf)+9 more\n\nThe stories that matter, in one email. Free — unsubscribe anytime.", "url": "https://wpnews.pro/news/inside-the-copper-to-optics-shift-in-ai-data-centers", "canonical_source": "https://mlq.ai/news/inside-the-copper-to-optics-shift-in-ai-data-centers/", "published_at": "2026-07-23 17:53:08.632055+00:00", "updated_at": "2026-07-23 17:53:10.876388+00:00", "lang": "en", "topics": ["artificial-intelligence", "ai-infrastructure", "ai-chips", "ai-research"], "entities": ["Broadcom", "Nvidia", "Cisco", "Lightmatter", "AMD", "Meta", "Microsoft", "OpenAI"], "alternates": {"html": "https://wpnews.pro/news/inside-the-copper-to-optics-shift-in-ai-data-centers", "markdown": "https://wpnews.pro/news/inside-the-copper-to-optics-shift-in-ai-data-centers.md", "text": "https://wpnews.pro/news/inside-the-copper-to-optics-shift-in-ai-data-centers.txt", "jsonld": "https://wpnews.pro/news/inside-the-copper-to-optics-shift-in-ai-data-centers.jsonld"}}