Optical technologies are playing an increasingly central role in how networks are built, scaled and operated. As demand for compute and connectivity grows, the innovations shaping data center infrastructure are increasingly influencing broadband networks as well.
At OFC 2026 in Los Angeles, those shifts came into focus.
OFC — the Optical Fiber Communication Conference and Exhibition — brings together researchers, component and system vendors, network operators and hyperscalers to assess where optical communications technology stands and where it’s heading. The event — the world’s largest gathering for optical networking and communications — is valuable because it shows where the industry’s engineering effort and investment are concentrating.
One theme cut across the plenary talks, technical sessions and show floor of the conference: optics is now the critical infrastructure layer for compute and network scaling, from the xPU (a general term for CPUs, GPUs and AI accelerators) all the way to the subscriber premises. This has direct implications for broadband operators and the work we do at CableLabs.
This year, several things stood out:
- Data center optical technologies — from CPO and OCS to 1600ZR pluggables and multi-rail line systems — are establishing building blocks that will serve broader network architectures over time. The coherent optics supply chain is maturing rapidly, with products increasingly relevant to access network applications.
- Hollow-core fiber is in production at hyperscale, and its implications extend beyond latency into ultra-long-span transmission and quantum security. We intend to determine what it means for our members’ networks.
- The fiber that our members own and operate is becoming more versatile — whether for connecting distributed compute sites, enabling new sensing capabilities, or supporting quantum-safe communications.
Continuing the Conversation at Tech Summit
CableLabs contributed directly to these discussions at OFC, particularly in coherent PON (CPON), fiber sensing and quantum-secure communications — areas that align closely with the trends highlighted above. These are also areas of focus within our ongoing Technology Vision work.
We’re continuing the conversation next month at CableLabs Tech Summit, exclusively for employees of CableLabs member companies and exhibiting vendors. At Tech Summit (April 27–29 in Westminster, Colorado), we’ll explore what these developments mean and how they inform the Technology Vision. Members can register here.
At OFC, these broader trends were reflected in the technical program — particularly in how optical technologies are evolving to support AI-driven compute and the growing importance of interconnect performance.
Photonics Moves Closer to the AI Data Center Compute Core
AI compute demand is growing at roughly 4.5× per year, outpacing the roughly 2× per-chip efficiency improvement every two years. That gap is pushing performance scaling toward parallel architectures where interconnection bandwidth becomes the bottleneck. OFC 2026 covered this across three domains.
In the scale-up domain (under 10 m), copper is running into physical limits, with passive reach dropping to roughly one meter at 200G/lane. Co-packaged optics (CPO) addresses this by placing optics adjacent to the switch or xPU, improving bandwidth density and reducing energy per bit.
Multiple implementations are in development: silicon photonics with external continuous-wave (CW) lasers, gallium arsenide (GaAs) Vertical-Cavity Surface-Emitting Laser (VCSEL) arrays targeting ~1 pJ/bit, and emerging approaches using microLEDs or indium phosphide (InP) modulators with semiconductor optical amplifiers (SOAs). In the scale-out domain (10 m to 10 km), pluggable transceivers remain the workhorse. Per-lane rates are moving from 200G (shipping) toward 400G/lane. And in the scale-across domain — data center interconnect (DCI) at metro to regional distances (10 km to 1,000+ km) — is where data center optics and broadband transport converge, and where relevance to cable operators becomes direct.
Three new multi-source agreements (MSAs) launched March 12, just ahead of OFC, and were a major topic at the show. Each agreement addresses a different piece of the interconnect problem: the OCI (Optical Compute Interconnect) MSA defines the wavelengths and modulation formats for an open optical scale-up interconnect for AI clusters; the Open CPX MSA specifies the socketed optical engine interface for co-packaged and near-package optics (NPO) designs, comparing with soldered-down CPO; and the XPO MSA defines a high-density, liquid-cooled pluggable form factor targeting 12.8 Tbps per module as an alternative path for operators that want high-density optical pluggables without going full CPO.
Optical circuit switching (OCS) also drew significant attention. OCS reconfigures fiber connectivity in the optical domain without packet processing, reducing both power and latency compared to electrical packet switches. Google has deployed custom MEMS-based optical circuit switches across its data centers for several years, replacing top-tier electrical spine switches. At OFC 2026, multiple implementation technologies were represented — MEMS, liquid crystal, piezoelectric and silicon photonics — with tradeoffs around insertion loss, port count, integration and transceiver re-lock time still being worked through.
Scale-Across: Where Data Center Optics Meets the Network
Power and resiliency constraints are pushing workloads across multiple data center sites, driving demand for higher-capacity, longer-reach photonic interconnects. Standardized pluggable coherent transceivers (ZR/ZR+) are displacing proprietary solutions in DCI, with both InP and silicon photonics platforms deployed. The push toward 1600ZR and extended-reach coherent variants is well underway.
This matters for cable operators because the same coherent pluggable technologies being validated at 400G and 800G for DCI are cascading into metro and regional transport — the aggregation layer that cable operators increasingly rely on for distributed access architectures. The thermal and spectral engineering being solved for data center scale-across applies directly to the coherent aggregation links connecting hubs, headends and edge sites across our members’ networks.
Coherent PON Continues to Gain Traction
We also observed that the conversation around coherent PON (CPON) was shifting from “if” to “when and how” — a trend that clearly accelerated this year. As mentioned, CableLabs had a notable presence in the PON-related programming at the conference.
- Dr. Curtis Knittle, VP of Wired Technologies, presented a panel on TWDM-PON and highlighted the key advantage of CPON: a coherent link is tunable and stackable, and its high receiver sensitivity opens up deployment flexibility — longer reach, higher split ratios, or both.
- Matt Schmitt, distinguished technologist, participated in a Broadband Forum session highlighting how CPON can be leveraged to enable a converged, multi-access platform supporting residential, business, mobile and Internet of Things (IoT) services on a single, unified infrastructure.
- On the research side, Dr. Haipeng Zhang, principal architect, presented two contributed papers addressing key barriers to cost-effective CPON deployment: DSP complexity and the need for low-cost lasers (a top-scored paper). These results move CPON closer to practical deployment by enabling the use of lower-cost DFB or DBR lasers at the ONU while maintaining robust 100G and 200G transmission performance.
Hollow-Core Fiber: From Field Trial to Ecosystem
Hollow-core fiber (HCF) showed clear progress toward practical deployment at OFC 2026. Workshop discussions highlighted major advances in anti-resonant HCF designs: attenuation approaching ~0.04 dB/km in research demonstration, single-draw lengths extending beyond 90 km, and multiple vendors demonstrating manufacturable, field-deployable fiber. Long-standing concerns around loss, modal interference, cabling, splicing and reliability are being addressed with data from early commercial deployments.
At this moment, HCF is not a universal replacement for standard single-mode fiber, but a strong complement where its advantages — lower latency, ultra-low nonlinearity and wide transmission bandwidth — deliver system-level value. Industry attention is now focused on scaling production, reducing cost and maturing the broader ecosystem for targeted deployment in DCI, metro and other high-value applications.
CableLabs is actively evaluating hollow-core fiber in our labs. We’re assessing what HCF could mean for broadband access and aggregation — particularly around latency improvement, higher-capacity aggregation and an intriguing secondary benefit: HCF’s low Raman scattering makes it a better medium for coexistence with quantum key distribution (QKD). We’ll explore that connection in a dedicated session at Tech Summit.
Sensing and Securing the Fiber Plant
Two additional threads at OFC 2026 are worth tracking: distributed fiber sensing and quantum-safe communications.
Distributed fiber sensing had a strong showing, spanning research, dedicated programming and commercial product demonstrations. A dedicated panel organized by CableLabs’ Dr. Karthik Choutagunta, principal architect — “From Access Fiber to Awareness Grid” — brought together operators, vendors and researchers to discuss field deployment challenges and emerging use cases: outage prevention, truck-roll reduction and sensing-as-a-service opportunities including traffic monitoring, perimeter security and pipeline protection.
For cable operators with extensive outside plant, the value proposition is straightforward: fiber already in the ground can serve as a dense sensor array for detecting vibrations, temperature changes and mechanical disturbances.
Quantum-safe communications also had visible momentum across both the technical program and the exhibition floor. On the research side, four different research trends emerged:
- Continuous variable (CV) QKD keeps pushing for higher key rate (50-500 Mb/s) at short distances less than 25 km
- Coexistence of quantum signals (either QKD or entanglement) with classical data traffic, not only in P2P links, but also in P2MP access networks. On this front, Dr. Jing Wang, principal architect at CableLabs, also presented a contributed paper demonstrating, for the first time, seamless integration of a BB84 QKD channel into both coherent PON and NG-PON2 over a 20 km, 32-user network without adding fiber, modifying the PON architecture, or attenuating classical data traffic.
- Standardization efforts from ETSI, ITU-T, IEEE, ISO/IEC and IETF, as discrete variable (DV) QKD becomes closer to deployment
- Photonic integrated chips based on silicon photonics for single photon generation, manipulation and detection.
There is also exploration about how distributed fiber sensing and quantum key distribution can coexist on the same fiber plant. The connection to hollow-core fiber applies here as well: HCF’s dramatically reduced Raman scattering makes it a more favorable medium for QKD over operationally meaningful distances, potentially removing one of the practical barriers to deploying quantum-safe key distribution over access and metro fiber.
Taking These Insights to Tech Summit
These trends from OFC reinforce a broader shift: optical technologies are no longer confined to the data center. They’re becoming foundational to how broadband networks are built and scaled.
At CableLabs, we’re actively evaluating what this means for access, aggregation and network architecture. We’ll share more about what we’re learning in our labs during Tech Summit next month in Westminster and in future posts on the CableLabs blog.
