Industry News
|
2026,09,07
The Physical Limits of Traditional Fiber Are Approaching
As 800G becomes the standard in computing centers, 1.6T is ramping up, and 3.2T is on the horizon, a previously overlooked issue has emerged: is the fiber itself still sufficient to carry these high‑speed signals? Traditional single‑mode fiber has been refined over decades, but its physical boundaries in terms of latency, nonlinearity, capacity density, and polarization stability are being increasingly challenged by computing power demands.
Three Emerging Fiber Technology Roadmaps
1. Hollow‑Core Fiber: The "Ultimate Blood Vessel" for AI Computing
Hollow‑core fiber replaces the solid silica medium with air for optical signal transmission. In conventional silica fiber, light travels through a dense medium with higher latency. Hollow‑core fiber allows light to travel through air, approaching the theoretical speed of light, reducing transmission time by approximately one‑third.
Key Advantages:
Ultra‑low latency: ideal for latency‑sensitive applications such as AI model training
Low nonlinear effects: more stable signal transmission
Low loss: performance continues to improve
Industry Progress: China's three major telecom operators have completed multiple pilot tenders for hollow‑core fiber. China Mobile deployed the first operator‑grade hollow‑core commercial line; China Telecom launched pilots in Zhejiang, Sichuan, and Chengdu; and China Unicom completed pilot network integration in Guizhou. Yangtze Optical Fibre and Cable (YOFC) has deployed over 10 commercial and pilot projects across Asia, Europe, and the Americas. In 2025, YOFC helped all three major operators deploy their respective world‑first hollow‑core fiber commercial lines, including the 100‑km Guangdong–Hong Kong project – the world's longest hollow‑core fiber commercial deployment. However, current tender prices are approximately RMB 25,000‑36,000 per core‑kilometer – hundreds of times higher than conventional G.652D single‑mode fiber. Large‑scale commercialization still awaits capacity ramp‑up and yield improvements.
2. Multi‑Core Fiber: A Key Enabler for Parallel Transmission
The value of multi‑core fiber extends beyond traditional space‑division multiplexing for high‑capacity long‑haul transmission; it is also deeply integrated with Micro‑LED optical interconnect technologies. Pioneering solutions such as Microsoft MOSAIC and Avicena LightBundle adopt "wide‑and‑slow" parallel transmission architectures, using arrays of Micro‑LEDs as light sources and multi‑core fiber as parallel signal carriers. A single multi‑core fiber integrates dozens or more cores, each paired with a Micro‑LED channel.
Application Scenarios: Short‑reach interconnect within AI computing racks and between boards – a key technical path for CPO (Co‑packaged Optics).
Current Status: The basic fiber technology for multi‑core is relatively mature, but supporting components (fan‑out devices, coupling schemes, field splicing, and standardized testing systems) remain underdeveloped, and the supporting ecosystem is still in its infancy.
3. Polarization‑Maintaining Fiber: The Foundation for High‑End Optical Components
Polarization‑maintaining (PM) fiber is a critical material for high‑end optical devices. As coherent optical modules continue to proliferate and silicon photonics and CPO technologies evolve, the demand for PM fiber in device applications is rapidly increasing. Industry focus is shifting from single polarization extinction ratio metrics to engineering parameters such as batch consistency, small‑form‑factor compatibility, and environmental resilience.
Domestication Progress: Chinese manufacturers have achieved domestic production of mid‑to‑low‑end PM fiber, while opportunities remain for import substitution in high‑end products for coherent and silicon photonic devices.
Common challenges across all three include preform manufacturing, yield, cost, fusion splicing, supporting devices, and testing standards. The technical prototypes have been validated, but the pace of commercialization and cost reduction is still being explored.
View More