Application of All-Photonics Network (APN) for Power Communication

To meet these, microwave radio and legacy optical TDM (Time Division Multiplexing) systems have traditionally been employed.

However, current infrastructures face end‑of‑life (EOL) and rising maintenance costs, and they cannot meet future large‑capacity demands essential for grid decarbonisation and digitalisation (e.g., AI‑based generation forecasting and predictive maintenance). To address both challenges, we focus on APN (All‑Photonics Network), a core technology of the IOWN concept. APN potentially provides stable low latency that conventional IP networks cannot guarantee, together with high capacity lacking in legacy TDM.

We premise APN transmission over existing OPGW (Optical‑fiber Composite Overhead

Ground Wire). Because OPGW is overhead, electromagnetic field variations from lightning can induce rapid changes in the state of polarization (SOP), with potential quality degradation.

Given APN’s novelty, it is essential to demonstrate that modern DSP/FEC can overcome

OPGW‑specific challenges.

This paper reports a long‑term field verification using an in‑service OPGW link initiated in

February 2025, quantitatively evaluating the effects of lightning and strong wind on communication quality. Initial results show steep SOP excursions coincident with nearby lightning. Crucially, even when SOP variation reached ~450 rad/ms, the pre‑FEC bit‑error rate (BER) remained ~10⁻⁴ without deterioration, and post‑FEC BER stayed zero—no service disruption occurred. These real‑world findings indicate that state‑of‑the‑art APN may tolerate lightning‑induced polarization fluctuations on OPGW. Nonetheless, under more severe conditions, DSP tracking limits might be exceeded; further characterisation of lightning impacts is needed to inform link designs that maintain connectivity during strikes.