OFC 2024 industry reflections: Part 2

Gazettabyte is asking industry figures for their thoughts after attending the recent OFC show in San Diego. Here are the thoughts from Ciena, Celestial AI and Heavy Reading.

Dino DiPerna, Senior Vice President, Global Research and Development at Ciena.

Power efficiency was a key theme at OFC this year. Although it has been a prevalent topic for some time, it stood out more than usual at OFC 2024 as the industry strives to make further improvements.

There was a vast array of presentations focused on power efficiency gains and technological advancements, with sessions highlighting picojoule-per-bit (pJ/b) requirements, high-speed interconnect evolution including co-packaged optics (CPO), linear pluggable optics (LPO), and linear retimer optics (LRO), as well as new materials like thin-film lithium niobate, coherent transceiver evolution, and liquid cooling.

And the list of technologies goes on. The industry is innovating across multiple fronts to support data centre architecture requirements and carbon footprint reduction goals as energy efficiency tops the list of network provider needs.

Another hot topic at OFC was overcoming network scale challenges with various explorations in new frequency bands or fibre types.

One surprise from the show was learning of the achievement of less than 0.11dB/km loss for hollow-core optical fibre, which was presented in the post-deadline session. This achievement offers a new avenue to address the challenge of delivering the higher capacities required in future networks. So, it is one to keep an eye on for sure.

Preet Virk, Co-founder and Chief Operating Officer at Celestial AI.

This year's OFC was all about AI infrastructure. Since it is an optical conference, the focus is on optical connectivity. A common theme was how interconnect bandwidth is the oxygen for AI infrastructure. Celestial AI agrees fully with this and adds the memory capacity issue to deal with the Memory Wall problem.

Traditionally, OFC has focused on inter- and intra-data centre connectivity. This year's OFC clarified that chip-to-chip connectivity is also a critical bottleneck. We discussed our high-bandwidth, low-latency, and low-power photonic fabric solutions for compute-to-memory and compute-to-compute connectivity, which were well received at the show.

It seemed that we were the only company with optical connectivity that satisfies bandwidths for high-bandwidth memory—HBM3 and the coming HBM4—with our optical chiplet.

Sterling Perrin, Senior Principal Analyst, Heavy Reading.

OFC is the premier global event for the optics industry and the place to go to get up to speed quickly on trends that will drive the optics industry through the year and beyond. There’s always a theme that ties optics into the overall communications industry zeitgeist. This year’s theme, of course, is AI. OFC themes are sometimes a stretch - think connected cars - but this is not the case for the role of optics in AI where the need is immediate. And the role is clear: higher capacities and lower power consumption.

The fact that OFC took place one week after Nvidia’s GTC event during which President and CEO Jensen Huang unveiled the Grace-Blackwell Superchip was a perfect catalyst for discussions about the urgency for 800 gigabit and 1.6 terabit connectivity within the data centre.

At a Sunday workshop on linear pluggable optics (LPO), Alibaba’s Chongjin Xie presented a slide comparing LPO and 400 gigabit DR4 that showed 50 per cent reduction in power consumption, a 100 per cent reduction in latency, and a 30 per cent reduction in production cost. But, as Xie and many others noted throughout the conference, LPO feasibility at 200 gigabit per lane remains a major industry challenge that has yet to be solved.

Another topic of intense debate within the data centre is Infiniband versus Ethernet. Infiniband delivers high capacity and extremely low latency required for AI training, but it’s expensive, highly complex, and closed. The Ultra Ethernet Consortium aims to build an open, Ethernet-based alternative for AI and high-performance computing. But Nvidia product architect, Ashkan Seyedi, was skeptical about the need for high-performance Ethernet. During a media luncheon, he noted that InfiniBand was developed as a high-performance, low-latency alternative to Ethernet for high-performance computing. Current Ethernet efforts, therefore, are largely trying to re-create InfiniBand, in his view.

The comments above are all about connectivity within the data centre. Outside the data centre, OFC buzz was harder to find. What about AI and data centre interconnect? It’s not here yet. Connectivity between racks and AI clusters is measured in meters for many reasons. There was much talk about building distributed data centres in the future as a means of reducing the demands on individual power grids, but it’s preliminary at this point.

While data centres strive toward 1.6 terabit, 400 gigabit seems to be the data rate of highest interest for most telecom operators (i.e., non-hyperscalers), with pluggable optics as the preferred form factor. I interviewed the OIF’s inimitable Karl Gass, who was dressed in a shiny golden suit, about their impressive coherent demo that included 23 suppliers and demonstrated 400ZR, 400G ZR+, 800ZR, and OpenROADM.

Lastly, quantum safe networking popped up several times at Mobile World Congress this year and the theme continued at OFC. The topic looks poised to move out of academia and into networks, and optical networking has a central role to play. I learned two things.

First, “Q-Day”, when quantum computers can break public encryption keys, may be many years away, but certain entities such as governments and financial institutions want their traffic to be quantum safe well in advance of the elusive Q-Day.

Second, “quantum safe” may not require quantum technology though, like most new areas, there is debate here. In the fighting-quantum-without-quantum camp, Israel-based start-up CyberRidge has developed an approach to transmitting keys and data, safe from quantum computers, that it calls photonic level security.