ECOC 2025 returned to Copenhagen in late September under the theme "Enabling the Next Generation of Communication". The timing couldn't be more relevant. AI infrastructure is reshaping optical networking at every layer, driving markets from $12-15 billion today to a projected $45 billion by 2030.
The show floor revealed coordinated innovation across the entire optical stack. We spent time with Coherent, our partner of 25 years, whose portfolio spans the full spectrum—pluggable transceivers, co-packaged optics, optical circuit switching, and test instrumentation.
Here's what matters for the networks being built today.
Understanding AI Data Center Architecture: Scale-Up vs. Scale-Out
AI infrastructure isn't monolithic. Understanding where different optical technologies fit requires recognizing distinct network domains.
Scale-up networks connect GPUs and XPUs to form a single compute core. Currently 100% copper at distances under 10 meters, these closed systems prioritize density and power consumption above all else. Scale-out networks connect those cores to create the AI factory—heterogeneous optical networks spanning 10 meters to 10 kilometers where flexibility and multi-vendor compatibility drive decisions.
Julie Eng, Coherent's CTO, laid out the framework: "In the front-end and scale-out portions, you see optical pluggable transceivers and that will continue for the majority of cases. But the scale-up domain is where we see potential for co-packaged optics like CPO, NPO, and CIO."
The shift matters because as AI pushes data rates higher, copper hits physical limits in scale-up networks. That creates a massive market expansion opportunity for optics—new revenue from applications that couldn't use optical solutions before.
The Pluggable Transceiver Roadmap: Still Growing Strong
Pluggable transceivers aren't going away. Coherent's market model projects $25 billion in pluggables by 2030, continuing growth through the decade. Why? Because the value proposition—flexibility, multi-vendor compatibility, security of supply—remains critical for most network applications.
The technology evolution is impressive. Coherent's portfolio spans 100 megabit to 1.6 terabit, built with the right optical technology for each application. VCSELs deliver lowest cost and power for short reach. Silicon photonics handles medium distances with efficient passive integration. Indium phosphide tackles the longest reaches and toughest specifications.
At OFC 2025, Coherent demonstrated 400G indium phosphide EMLs—the building blocks for 3.2T, 6.4T, and higher data rates. The roadmap has two paths: increase lane speeds (200G, then 400G per lane) and increase lane counts (from eight lanes to 16, 32, 64 lanes via new high-density connectors).
Stefan Kohler put it simply: "We're making 1.6T out of 200 gigabit per second individual lanes with EMLs and silicon photonics—we have a whole menu of technologies we bring to bear."
Manufacturing cycles tell the story. Ramping from 10,000 to 10 million units took a decade at 10G. Now it takes three years. The pace keeps accelerating.
Co-Packaged Optics: The Right Tool for Specific Jobs
CPO generates headlines, but the reality is more nuanced. It's pluggable transceiver technology miniaturized and moved inside the box next to the switch or XPU chip.
Why do it? Eliminate power-hungry electrical traces to the front faceplate. Improve bandwidth density by requiring only fiber through the front panel.
The trade-off? You lose architectural flexibility. With pluggables, you can decide after deployment which ports go 30 meters with VCSELs, 500 meters with silicon photonics, or 10 kilometers with indium phosphide. CPO locks those decisions in at manufacturing.
Julie Eng explained the market logic: "CPO eliminates that flexibility, which is why we see it primarily in scale-up where power and density trump other concerns."
Coherent develops both VCSEL-based CPO (targeting one picojoule per bit efficiency) and silicon photonics CPO (offering longer reach and optical circuit switching compatibility). The market model shows CPO growing to $5 billion by 2030—significant, but one-fifth the pluggable market.
Multiple technologies will coexist in CPO just like they do in pluggables. Each fits specific applications. That's not changing.
Optical Circuit Switching: Dynamic Network Reconfiguration
Optical circuit switching solves a different problem: dynamic network reconfiguration without manual intervention. This isn't the failed optical switching of 2000. This is software-defined circuits built on proven digital liquid crystal technology.
The applications keep expanding. AI clusters that need different configurations for different training jobs. Network resiliency through automatic failover to spare racks. Use cases across front-end, scale-out, scale-up, and data center interconnect.
Chris Johnson highlighted the power efficiency angle: "Seven years ago, Google recognized the need to reduce energy consumption. Our spine switch stays in the optical domain and takes 75 watts. With pluggable transceivers at 20 watts each, the power draw would be massive."
Coherent demonstrates systems from 64x64 to 320x320 ports with roadmap to higher counts. OCS-optimized transceivers compensate for insertion loss while remaining standards-compliant. The market projection: $2 billion by 2030, created from zero.
Data Center Interconnect: Coherent Optics Enable IP-Over-DWDM
AI workloads exceed single data center capacity. That drives demand for higher-speed interconnects between facilities.
Coherent's 100G ZR family delivers coherent transmission in QSFP28 form factor. Kevin Affolter, Product Line Manager, explained the breakthrough: "The QSFP28 form factor plugs directly into existing 100G router ports. Network operators can reuse all those routers while upgrading from 10 gigabits to 100 gigabits using existing fiber plant."
This enables IP-over-DWDM architectures. You go straight from router to line system. No transponder boxes. No gray optics. Simpler architecture, lower cost, fewer failure points.
Since launching mid-2024, the product line expanded through multiple variants: -8 dBm and 0 dBm power versions, commercial and industrial temperature ranges (-40°C to +85°C), and a bidirectional version now sampling.
Kevin described the BiDi variant impact: "If a customer has two fibers, this doubles their capacity while increasing per-fiber bandwidth 10x and extending reach from 80km to 300km."
The broader DCI market spans 400G, 800G, and 1.6T coherent transceivers. Coherent uses indium phosphide where specifications demand it—like hitting 0 dBm without internal micro-EDFAs using semiconductor optical amplifiers. Silicon photonics goes where it can meet specs with cost advantages.
Market projection: $4 billion by 2030.
Transport Networks: Multi-Rail Solves the Capacity Challenge
AI workloads now stress transport infrastructure in unexpected ways. Customers need 10 petabits per second through inline amplifier huts with fixed size and power budgets.
The math is brutal. Today's standard of 16 fiber pair "rails" per ILA hut means 10 Pbps requires 256 fiber pairs across 16 huts.
Julie Eng outlined the solution: "With first-generation multi-rail, we can scale that down by 4x. Long-term, the goal is fitting all 256 pairs in today's single hut."
The technology combines power-efficient uncooled pump lasers, optimized packaging, shared metrology (one dynamic gain equalizer covering four rails instead of four separate units), parallelized passive components, and switchable metrology.
Coherent demonstrated multi-rail at OFC 2025 with an advanced version at ECOC 2025. The industry needs this capability now.
Test and Measurement: Instrumentation That Keeps Pace
Network evolution demands better characterization tools. Coherent's instrumentation portfolio addresses production and R&D requirements.
Key products launched and demoed at OFC and ECOC 2025:
- WaveAnalyzer 1500B (launched): C+L band coverage with 100 MHz absolute frequency accuracy—wavelength meter precision in a spectrum analyzer.
- WaveAnalyzer 200B (launched): Super C-band with 650 MHz resolution bandwidth, portable format with touchscreen and four-hour battery. Ships November 2025. The coherent detection technology enables lab-grade measurements in field-deployable form.
- WaveShaper 32000B: 32 ports configurable as 1x31, 4x28, or 16x16 for multiplexing and demultiplexing. The product line spans 1 micron through U-band to 1650nm.
- WaveShaper 500B: Recently added super C+L band capability for transceiver noise sensitivity testing in manufacturing.
- WaveMaker 4000A: Generates COM signals using ASE combined with real transmitted laser light for system validation under realistic conditions.
Beyond 2030: Quantum Security and Emerging Technologies
Coherent demonstrated quantum key distribution in QSFP form factor with Qubitekk, HPE, Juniper, and Liberty Global. Quantum computers are projected to break traditional encryption by 2030. QKD has existed, but in refrigerator-sized boxes. This demonstration showed successful quantum key transmission alongside regular traffic in a standard pluggable form factor.
Other developments include dispersion compensation modules for 1.6T transceivers extending reach to 6 kilometers, offering cost-effective range extension versus full coherent solutions.
What This Means for Network Builders
The AI-driven market expansion to $45 billion by 2030 creates opportunities across the entire optical ecosystem. But success requires understanding where different technologies fit.
Pluggables maintain dominance where flexibility and multi-vendor ecosystems matter. CPO serves specific applications where power and density override flexibility concerns. Optical circuit switching enables dynamic reconfiguration. Coherent DCI modules simplify architecture through IP-over-DWDM. Multi-rail technology addresses transport capacity constraints.
Chris Johnson framed the innovation challenge: "The biggest issue is that transceivers consume more power as data rates increase. We focus on thermal management using our silicon carbide background while working with DSP partners on 5-nanometer, 3-nanometer processes to reduce power consumption. And we're bringing out 400 gig EML technology that enables the 1.6 and 3.2 terabit generation needed in the next five years."
Julie Eng captured the moment: "The speed with which we're changing data rates is getting faster and faster. We have less time to innovate between every data rate. For high-tech companies with technologies in-house, when technologies shift faster, that benefits the technology leader."
For EPS Global, 25 years of partnership with Coherent means navigating technology transitions together. This moment is different—not technology replacement, but coordinated innovation across every layer. Markets are expanding. Applications are multiplying. The networks being built today need solutions across the spectrum.
The pace keeps accelerating. The challenges keep getting harder. And the opportunities keep growing.
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