2025 is a key year for fgOTN to move from standards to large-scale application. fgOTN bridges traditional SDH and OTN, delivering 10M small-granularity hard pipes, reliable isolation, and ultra-low latency. This makes it the cornerstone of communications for new power systems, intelligent transportation, and computing networks.
This year has seen accelerated progress in fgOTN standardization. At the end of 2023, the International Telecommunication Union (ITU-T) officially released the fgOTN standard as an enhancement to OTN, providing the technical foundation for a smooth evolution from SDH to next-generation optical transport network in industries such as electric power. In 2025, the China Communications Standards Association (CCSA) approved a series of industry standards, including Technical requirements for fine grain Optical Transport Network (fgOTN) (YD/T 6439-2025) and Technical requirements for control and management of Optical Service Unit (OSU) and fine grain Optical Transport Network (fgOTN) Based OTN (YD/T 6438-2025). In October, the National Energy Administration of China incorporated the Engineering Design Specifications for Fine-Grain Optical Transport Network (fgOTN) of Power System into the energy industry standard development plan. This marks another major step in fgOTN energy industry standardization, following the establishment of international and national standards. It also provides authoritative support for engineering deployment in the energy sector. At the same time, the International Council on Large Electric Systems (CIGRE) officially approved the establishment of the WG D2.65 “Optical Transport Communication Networks for Electric Power Utilities”, led by experts from the China Electric Power Research Institute. The working group focuses on applying next-generation optical communication technologies such as fgOTN in the electric power industry, providing technical references for global electric power communication evolution.
The establishment of standards expedites the development of a global industry consensus. In June 2025, at the Africa Energy Forum in Cape Town, South Africa, several African power enterprises, together with industry partners, jointly released the fgOTN White Paper for Electric Power (for Africa), outlining a technical roadmap for the digitalization of African power grids. In November 2025, at the GCC POWER conference in Kuwait, CIGRE GCC and international communications enterprises jointly released the fgOTN White Paper for Electric Power (for Middle East). The white paper addresses ICT infrastructure development in the AI era for the electric power industry and promotes industry intelligence through technological innovation.
From a practical perspective, 2025 is regarded as the inaugural year of large-scale fgOTN commercialization. Over the course of one year, the State Grid Corporation of China verified critical production services such as teleprotection and differential control on the fgOTN communications system across several provinces. Results show latency can be stably controlled at the millisecond level and reliability reaches 99.999%. The end-to-end solutions provided by related equipment suppliers have passed the strict test of the power production environment. Power grids in multiple regions have launched pilot projects to enable a smooth migration from SDH to fgOTN. The hybrid networking mode—retaining legacy services while migrating new services to fgOTN—ensures the security of existing systems while meeting the demands of emerging services, such as renewable energy and AI-based inspection, with bandwidth flexibility and deterministic transmission. Globally, power enterprises—including Mozambique EDM—have begun verifying fgOTN technology and progressively deploying it in new communications networks, laying the foundation for future digital service development.
On August 21, State Grid Corporation of China, China Southern Power Grid, Chinese Society for Electrical Engineering, and China Energy Research Society, together with leading institutions and enterprises, jointly released the White Paper on Communication Target Networks of the Future Power System. Aiming to achieve wide consensus, the paper assembles expertise from the industry to map out top-level design and implementation path for communication networks suited to new power systems, contributing to the “dual-carbon” goal. The white paper explicitly identifies fgOTN as the next-generation evolutionary successor to SDH. At the Power Information and Communication Technology Conference, the IEEE PES Technical Committee on Power System Communications and Cybersecurity – China (IEEE PES PSCCSTC) and the IEEE PES PSCCSTC Power Communication Innovation Subcommittee jointly released fgOTN Electric Power Application Practices, aiming to establish industry consensus. Building on the earlier white paper, it offers guidance on key communication technologies and practical pathways for developing new power systems.
Reflecting on 2025, it is clear that fgOTN made a decisive transition: evolving from technical standards to global industry consensus, and advancing from pilot verification to widespread deployment. fgOTN addresses the challenge posed by traditional OTN’s excessively large granularities and SDH’s limited maximum bandwidth, where future evolution and efficiency could not be simultaneously achieved. It also provides hard pipes to underpin the digital future of new power system, transportation system, and the AI era. In 2025, fgOTN transitioned from lab-based research and theoretical exploration to production networks, marking a significant milestone in the evolution of optical communications.
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