I’m thrilled to sit down with Matilda Bailey, a renowned networking specialist whose expertise in cellular, wireless, and next-generation solutions has made her a go-to voice in the evolving world of data center interconnect (DCI) and optical networking. With DCI experiencing unprecedented growth and technologies like coherent pluggables and modular optical systems reshaping the landscape, Matilda offers a unique perspective on how these innovations are tackling the industry’s biggest challenges. In our conversation, we explore the drivers behind DCI’s rapid expansion, the transformative power of cutting-edge optical solutions, the operational nuances for hyperscalers and service providers, and the strategies for scaling networks in diverse and constrained environments.
How would you describe the forces behind the staggering 50% annual growth in data center interconnect, particularly with hyperscalers and communication service providers, and what does this mean for network planning?
Thanks for having me, Kendra. The 50% annual growth in DCI is nothing short of a tidal wave, and it’s primarily fueled by the insatiable demand for data processing and storage, especially from hyperscalers and CSPs who are scaling at a breakneck pace. Think about the explosion of cloud services, AI workloads, and streaming platforms—every bit of that data needs to move between data centers seamlessly, and that’s where DCI comes in. For hyperscalers, it’s about building massive, private networks to handle their own traffic, while CSPs are juggling diverse customer needs alongside their own growth. I recall working with a major CSP last year who had to completely rethink their network topology because their traffic doubled in just 18 months—they were caught off guard and had to rush capacity upgrades. This kind of growth forces network planners to think far beyond traditional models; they’re now prioritizing scalable, modular solutions and over-provisioning capacity to avoid being blindsided again. It’s a high-stakes game, because underestimating demand can mean outages, and overbuilding eats into margins. You feel the tension in every planning meeting—everyone’s trying to predict the unpredictable.
Can you unpack the incredible efficiency of 800G ZR/ZR+ coherent pluggables, which deliver up to 1,700 kilometers with just 30 watts of power in a tiny QSFP-DD package, and share a story of how this technology plays out in the real world?
Absolutely, the efficiency of 800G ZR/ZR+ coherent pluggables is a game-changer, and it’s a testament to how far we’ve come in optical tech. The secret sauce is a combination of advanced 3nm digital signal processing geometry and sophisticated modulation techniques that were once exclusive to bulky embedded engines. These pluggables pack all that power into something you can literally hold in your hand, using less than 30 watts to push 800 Gb/s over 1,700 kilometers. I was part of a deployment last year for a regional hyperscaler connecting data centers across a sprawling 1,500-kilometer network. We plugged these into their routers directly, bypassing traditional transponders, and watched in awe as the system lit up with minimal power draw—it felt like magic seeing those metrics on the dashboard. The step-by-step was straightforward: we slotted the QSFP-DD modules into their switches, configured the IP-over-DWDM setup, and fine-tuned the signal for long-haul stability. The result was a drastic cut in their operational costs and rack space, which they hadn’t expected to be so significant. It’s not just tech; it’s a lifeline for operators squeezed by power and space constraints.
Hyperscalers have led the charge with the IP-over-DWDM model using coherent pluggables, starting with 400G ZR. What’s so compelling about this approach for their private DCI networks, and can you share an experience of transitioning to 800G ZR/ZR+?
The IP-over-DWDM model is a no-brainer for hyperscalers because it slashes complexity, space, and cost in one fell swoop. By integrating coherent pluggables directly into routers and switches, they eliminate layers of equipment, which means less power draw and fewer failure points. For their private DCI networks, where they control end-to-end traffic, this approach is like streamlining a highway—fewer toll booths, faster travel. I worked with a hyperscaler on their shift from 400G ZR to 800G ZR/ZR+ about six months ago, and it was eye-opening. They were handling massive AI training data across two campuses, but their 400G setup was hitting capacity limits. Upgrading to 800G doubled their throughput per port, but the challenge was ensuring compatibility with their existing optical line system—there were nights of sweating over signal integrity tests because even a tiny mismatch could tank performance. We had to tweak the modulation settings repeatedly and deal with some unexpected latency spikes. In the end, seeing their network stabilize with 800G felt like summiting a mountain after a grueling climb—the relief was palpable, and their team was thrilled to future-proof their infrastructure.
Thin transponders seem to strike a balance for CSPs, offering operational consistency with benefits like 50% less space and 40% less power per bit. How do they handle advanced features like bandwidth virtualization, and can you walk us through a practical example?
Thin transponders are a sweet spot for CSPs who need the perks of coherent pluggables but can’t fully commit to the IPoDWDM model due to operational diversity. These sleds or modules support multiple pluggable ports and enable features like bandwidth virtualization, which is essentially splitting and recombining traffic across wavelengths to maximize efficiency. For instance, you can take three 400G client feeds and map them to two 600 Gb/s line-side wavelengths, ensuring no capacity goes to waste. I saw this in action with a CSP managing a metro network for enterprise clients—they were struggling with uneven traffic loads and needed a way to dynamically allocate bandwidth. We deployed thin transponders, set up the virtualization to balance their 400G clients across 600 Gb/s wavelengths, and monitored it over a few weeks. The result was a 50% reduction in rack space and a 40% drop in power per bit, which they could directly correlate to cost savings on their energy bill. It felt like fine-tuning an orchestra—every piece had to harmonize, and when it did, the efficiency was music to their ears. This kind of solution keeps operations familiar while delivering massive gains.
The flexible open optical line system with innovations like the 64+ port C+L ROADM, delivering over 50 Tb/s with 800G pluggables, seems pivotal for DCI. Why is this modularity so essential, and can you share a specific setup that showcases its scalability?
Modularity in optical line systems, like the 64+ port C+L ROADM, is critical because DCI needs are incredibly diverse—from a few terabits on a single fiber pair to hundreds of terabits across multiple pairs. This flexibility lets operators mix and match components to suit specific demands without overhauling entire systems, saving both time and capital. With 800G ZR/ZR+ pluggables, a single 64+ port setup can push over 50 Tb/s, which is staggering for high-density routes. I worked on a setup for a large data center campus interconnection where we deployed this exact C+L ROADM configuration to handle traffic across 64 wavelengths in combined C and L bands. It was like building a superhighway for data—starting with a baseline of 30 Tb/s, we scaled to over 50 Tb/s in under a month by adding more 800G pluggables as demand spiked. The scalability was seamless; we didn’t need to rip and replace anything, just plug in and configure. I remember the relief on the team’s faces when we hit that 50 Tb/s mark during peak load testing—it was proof that modularity isn’t just a buzzword, it’s a survival tactic for DCI’s wild growth.
With data center builds spreading into diverse geographies due to real estate and power constraints, what unique connectivity challenges emerge, and how are solutions like in-line amplifiers adapting to tight spaces like small huts?
The push into diverse geographies for data centers creates a whole new set of connectivity headaches. You’re dealing with varied terrain, inconsistent power availability, and often limited infrastructure—think small huts instead of sprawling facilities. Every 60 to 100 kilometers, you need in-line amplifiers (ILAs) to boost signals, but these locations often have severe space and power constraints. I was involved in a multi-rail DCI project across a rural stretch where we had to deploy ILAs in tiny roadside huts barely bigger than a closet. The heat inside was brutal, and we had almost no room to maneuver. The solution was a newer generation of ILAs that consolidate support for up to eight fiber pairs into a single module, shrinking the footprint dramatically. We managed to fit everything into that cramped space, connecting multiple fiber pairs for hundreds of terabits of capacity. It was a grind—cables everywhere, sweat dripping as we worked—but seeing the signal strength hold steady across those long hauls made it worth it. These innovations are literally squeezing high performance into the tightest corners.
With data center capex projected to hit $1 trillion by 2030, how are operators prioritizing scalable DCI solutions, and what role do technologies like coherent pluggables play in future-proofing these networks?
That $1 trillion projection by 2030 is a wake-up call for operators—it signals that data center growth isn’t just a trend, it’s a tectonic shift. Operators are laser-focused on scalable DCI solutions that can grow with demand without breaking the bank, prioritizing technologies that offer both high capacity and operational flexibility. Coherent pluggables, like the 800G ZR/ZR+, are central to this because they deliver massive throughput—up to 800 Gb/s over 1,700 kilometers—while cutting power and space needs, which directly impacts capex and opex. I worked with a wholesale transport provider recently who adopted these pluggables across their backbone to prepare for AI-driven traffic surges. They started with a 400G baseline and scaled to 800G within a quarter, avoiding a complete infrastructure overhaul and saving millions in upfront costs. The metrics were clear: their power per bit dropped significantly, aligning with long-term sustainability goals. It’s not just about keeping up; it’s about staying ahead of the curve. When you deploy these technologies, you’re not just solving today’s problems—you’re building a foundation for tomorrow’s unknowns, and there’s a quiet confidence in knowing your network won’t buckle under pressure.
What is your forecast for the future of DCI as these technologies continue to evolve and data demands keep soaring?
Looking ahead, I see DCI becoming even more dynamic and intelligent, driven by relentless data demand and the ongoing AI boom. We’re likely to see coherent pluggables pushing beyond 800G to 1.2 Tb/s and higher within the next few years, with power efficiencies that will blow today’s benchmarks out of the water. Modular optical systems will become smarter, integrating AI for predictive traffic management to optimize capacity in real-time. I also anticipate a deeper push into challenging geographies, with solutions like compact, multi-rail ILAs becoming standard to tackle space constraints. The real game-changer will be how operators balance cost with innovation—there’s a palpable excitement in the industry about what’s possible, but also a cautious realism about margins. I think we’re on the cusp of a DCI revolution where networks don’t just connect data centers; they anticipate and adapt to needs before they even arise. It’s going to be a wild ride, and I can’t wait to see where we land.
