C114 News, Special Report on October X (Jiang Junmu) — As the global wave of digital and intelligent transformation enters a critical stage, network infrastructure, as the cornerstone of economic and social operations, is undergoing a comprehensive overhaul, spanning both technical architecture and business applications.
Recently, Ronald Freund, Head of Department Photonic Networks and Systems, Chief of F5G OpenLab, Fraunhofer Heinrich Hertz Institute (HHI), delivered a speech titled "Next-Generation High-Speed Optical Access Networks" at the All-Optical Access Forum held during HUAWEI CONNECT 2025. In his speech, he highlighted the latest advancements in F5G and its future trajectory, emphasizing the pivotal role of fiber access as a sustainable, high-performance network foundation. He also envisioned the transformative potential of F5G Advanced (F5G-A) in driving industrial automation to enable green and low-carbon development, as well as accelerate AI convergence.
From the "last mile" to the "last meter," and from "fiber to the home (FTTH)" to "Fiber to Everything," F5G and F5G-A are redefining the future of connectivity, energy efficiency, and intelligent infrastructure.
Beyond speed: Defining the next-generation high-speed optical access networks
The explosive growth of global data traffic—coupled with the widespread adoption of emerging applications such as AI, 8k video, cloud computing, big data, and IoT—is placing unprecedented demands on the bandwidth, latency, and reliability of fixed networks. In this context, F5G and its evolutionary successor, F5G-A, have emerged to unlock the full potential of fiber access through continuous technological innovation and address the future demands of society for high-speed, reliable, and environmentally sustainable communications.
In 2019, the European Telecommunications Standards Institute (ETSI) launched the Industry Specification Group (ISG) F5G to systematically define generations of fixed networks. The initiative aims to bridge gaps across industry sectors through unified technical specifications, as well as to foster the overall growth of the industry ecosystem. F5G and 5G are now emerging as two cornerstones of the digital world, jointly supporting the digital and intelligent upgrade of countless households and industries.
Ronald Freund emphasized in his speech that F5G is not merely about boosting speed—it is driving breakthroughs across three key dimensions: Enhanced Fixed Broadband (eFBB), Full-Fiber Connectivity (FFC), and Guaranteed Reliable Experience (GRE). Compared with F4G, F5G delivers ten times higher bandwidth, ten times higher connection density, and ten times lower latency, accelerating the evolution from FTTH to "Fiber to Everything." Compared with F5G, F5G-A delivers a further tenfold increase in bandwidth, fiber connection density, and energy efficiency—all while enhancing network reliability from 99.999% to 99.9999%. It also enables meter-level precision sensing, sub-millisecond latency, and supports Level-4 autonomous networking. In addition, it can provide ubiquitous 10 Gbit/s access to extend optical fibers from homes to rooms, machines, and devices. These advancements power applications such as industrial production and remote healthcare, where highly deterministic service-level agreements (SLAs) are essential.
All-scenario enablement: Proof of concepts in the F5G OpenLab
To accelerate the popularization of F5G and the maturity and application of F5G-A, Fraunhofer HHI and industry-leading enterprises, such as Huawei, jointly established the F5G OpenLab. The lab not only provides an advanced testing environment and equipment, but also brings together researchers and engineers from around the world to conduct proof-of-concept work. Key focus areas include cloud-based machine vision, control of automated guided vehicles (AGVs) and robots, multi-service PON for video management, and the integration of generative AI into F5G-A/F6G optical network architectures.
With carbon neutrality as a common global goal, the energy consumption of communication technologies is increasingly drawing attention. Ronald Freund cited the greenhouse gas emissions of HD video streaming in data centers and networks as an example. After comparing 3G, 4G, 5G, VDSL, and FTTH, the lab concluded that FTTH is the most energy-efficient technology in terms of carbon emissions. Under identical conditions, FTTH produces around 40% of the carbon dioxide generated by 5G per hour.
In the industrial field, only low-latency, high-reliability, and easy-to-expand networks can truly support flexible manufacturing and closed-loop control in the era of Industry 4.0. Compared with traditional switch networks, passive optical networks (PONs) offer simplified deployment—with no need for cabinets—and are inherently immune to electromagnetic interference. PONs are projected to reduce power consumption by over 30%, significantly lowering operational costs for energy-intensive environments such as data centers, factories, and campuses. At the same time, they support green, low-carbon development and align with enterprises' ESG strategies.
Future evolution: Coexistence of IM-DD, coherent communication, and SDM
In terms of optical access technology, Ronald Freund introduced the clear evolution path from GPON to XGS-PON and 25G/50G PON. However, he also noted that the future evolution of PONs may follow a "dual-track" approach: In cost-sensitive scenarios such as FTTH and FTTR, traditional intensity modulation with direct detection (IM-DD) technology will continue to dominate; whereas in performance-critical domains—like performance-sensitive enterprise private lines—emerging coherent technologies and space-division multiplexing (SDM) will be gradually adopted.
He highlighted SDM-PON technology, which is based on loosely-coupled multi-core fibers. SDM-PON enables ultra-high capacity ranging from 4 × 25 Gbit/s to 8 × 100 Gbit/s, with a low split ratio. These fibers support cost-effective 1,300 nm optical transmission using intensity modulation and direct detection, while preserving a similar architecture and O&M mode to existing PON systems.
In addition, coherent optics is regarded as a key enabler for 200G/400G symmetric transmission in next-generation ultra-high-speed PONs, thanks to its high spectral efficiency and flexible subcarrier allocation. As the cost of short-reach coherent modules continues to decline, coherent PON is expected to gradually be commercialized in the coming years.
Conclusion: The future is here, led by optical innovation
Ronald Freund's speech not only provided a systematic overview of the technical evolution and industry value of F5G and F5G-A, but also envisioned a digital and intelligent society where "fiber links all things, and intelligence grows within." In the evolution to next-generation high-speed optical access networks, we witness not only exponential increases in bandwidth and reductions in latency, but also a fundamental transformation of optical networks—from mere "channels" to intelligent "platforms," and from basic "tools" to integrated "ecosystems."
The future is here, led by optical innovation. With continuous technological innovation and cross-industry cooperation, F5G-A is expected to achieve large-scale global commercial deployment in the coming years. Driven by this, a new era of efficiency, sustainability, and intelligence is set to rapidly unfold.