Lumentum's optical circuit switch for AI data centres

Part 3: Data Centre Switching

The resurgence of optical circuit switches for use in data centres is gaining momentum, driven by artificial intelligence (AI) workloads that require scalable connectivity.

Peter Roorda

Lumentum is one of several companies that showcased an optical circuit switch at the OFC event in San Francisco in March.

Lumentum's R300 switch connects optically the 300 input ports to any of the 300 output ports. The optical circuit switch uses micro-electro-mechanical systems (MEMS), tiny mirrors that move electrostatically, to direct light from an input port to one of the 300 output ports.

The R300 addresses the network needs of AI data centres, helping link large numbers of AI accelerator chips such as graphics processor units (GPUs).

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Tomahawk 6: The industry’s first 100-terabit switch chip

Part 2: Data Centre Switching

Peter Del Vecchio, product manager for the Tomahawk switch family at Broadcom, outlines the role of the company’s latest Tomahawk 6 Ethernet switch chip in AI data centres.

Peter Del Vecchio

Broadcom is now shipping samples of its Tomahawk 6, the industry’s first 102.4-terabit-per-second (Tbps) Ethernet switch chip.

The chip highlights AI's impact on Ethernet networking switch chip design since Broadcom launched its current leading device, the 51.2-terabit Tomahawk 5.

The Tomahawk 6 is more evolutionary, rather than a complete change, notes Del Vecchio.

The design doubles bandwidth and includes enhanced networking features to support AI scale-up and scale-out networks.

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Oriole’s fast optical reconfigurable network

Part 1: Data Centre Switching

• Start-up Oriole Networks has developed a photonic network to link numerous accelerator chips in an artificial intelligence (AI) data centre.

• The fast photonic network is reconfigurable every 100 nanoseconds and is designed to replace tiers of electrical switches.

• Oriole says its photonic networking saves considerable power and ensures the network is no longer a compute bottleneck.

Georgios Zervas, CTO of Oriole Networks.

In a London office bathed in spring sunlight, the team from Oriole Networks, a University College London (UCL) spin-out, detailed its vision for transforming AI and high-performance computing (HPC) data centres.

Oriole has developed a networking solution, dubbed Prism, that uses fast reconfigurable optical circuit switches to replace the tiers of electrical packet switches used to connect racks of AI processors in the data centre.

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OFC 2025 industry reflections - Final Part

Gazettabyte has been asking industry figures for their thoughts after attending the OFC conference held in San Francisco.

In the final part, Arista’s Vijay Vusirikala and Andy Bechtolsheim, Chris Doerr of Aloe Semiconductor, Adtran’s Jörg-Peter Elbers, and Omdia’s Daryl Inniss share their learnings. Vusirikala, Doerr, and Elbers all participated in OFC’s excellent Rump Session.

Muir Woods National Monument, outside San Francisco

Vijay Vusirikala, Distinguished Lead, AI Systems and Networks, and Andy Bechtolsheim, Chief Architect, at Arista Networks.

OFC 2025 wasn't just another conference. The event felt like a significant momentum-gaining inflexion point, buzzing with an energy reminiscent of the Dot.com era optical boom.

This palpable excitement, reflected in record attendance and exhibitor numbers, was accentuated for the broader community by the context set at Nvidia’s GTC event held two weeks before OFC, highlighting the critical role optical technologies play in enabling next-generation AI infrastructure. 

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OFC 2025 industry reflections - Part 3

Gazettabyte is asking industry figures for their thoughts after attending the OFC show in San Francisco. In the penultimate part, the contributions are from Cisco's Bill Gartner, Lumentum's Matt Sysak, Ramya Barna of Mixx Technologies, and Ericsson's Antonio Tartaglia.

San Francisco skyline. Source: Shutterstock

Bill Gartner, Senior Vice President and General Manager, Optical Systems and Optics, Cisco  

There was certainly much buzz around co-packaged optics at Nvidia’s GTC event, and that carried over into OFC.

The prevailing thinking seems to be that large-scale co-packaged optics deployment is years away. While co-packaged optics has many benefits, there are challenges that need to be overcome before that happens.

Existing solutions, such as linear pluggable optics (LPO), continue to be discussed as interim solutions that could achieve close to the power savings of co-packaged optics and preserve a multi-vendor pluggable market. That development in the industry will be an intermediate solution before co-packaged optics is required.

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Avicena partners with TSMC to make its microLED links

TSMC, the leading semiconductor foundry, will make the photo-detectors used for Avicena Tech’s microLED optical interconnect technology.

Christoph Pfistner

Avicena is developing an optical interface that uses hundreds of parallel fibre links - each link comprising a tiny LED tranmitter and a silicon photo-detector receiver - to deliver terabit-per-second (Tbps) data transfers.

Avicena is targeting its microLED-based interconnect, dubbed LightBundle, for artifical intelligence (AI) and high-performance computing (HPC) applications.

The deal is a notable step for Avicena, aligning its technology with TSMC’s CMOS manufacturing prowess. The partnership will enable Avicena to transition its technology from in-house prototyping to high-volume production.

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OFC 2025 industry reflections - Part 2

Gazettabyte is asking industry figures for their thoughts after attending the 50th-anniversary OFC show in San Francisco. In Part 2, the contributions are from BT's Professor Andrew Lord, Chris Cole, Coherent's Vipul Bhatt, and Juniper Network's Dirk van den Borne.

Exhibition floor. Source: OFC

Professor Andrew Lord, Head of Optical Network Research at BT Group

OFC was a highly successful and lively show this year, reflecting a sense of optimism in the optical comms industry. The conference was dominated by the need for optics in data centres to handle the large AI-driven demands. And it was exciting to see the conference at an all-time attendance peak.

From a carrier perspective, I continued to appreciate the maturing of 800-gigabit plugs for core networks and 100GZR plugs (including bidirectional operation for single-fibre working) for the metro-access side.

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