China Mobile transmitted a real-time 1.6 terabits per second single-wavelength signal over 960 kilometers of standard backbone fiber using a symbol rate of 230 gigabaud, state media reported on November 11, 2026.

The test represents the carrier’s longest single-wavelength 1.6T transmission to date and sets a technical benchmark for long-haul optical links running on legacy G.652.D glass.

Carried out with unnamed equipment partners, the field trial pushed symbol rates to 230 gigabaud to multiply throughput without widening spectral allocations. G.652.D single-mode fiber forms the physical core of most national and international telecommunications grids, yet engineers designed it decades before multi-terabit optical transport existed. Demonstrating that existing fiber paths can sustain 1.6T over nearly 1,000 kilometers indicates network operators can defer costly civil works by upgrading optoelectronics at terminal nodes instead.

Baud rate measures the volume of signal transitions transmitted every second. Raising this rate allows a carrier to pack more data into an individual wavelength while leaving the underlying modulation format unchanged.

China Mobile began deploying commercial 400G systems across its all-optical backbone network at scale in 2024, relying primarily on 130 gigabaud transceivers. Subsequent metropolitan trials at 1.2T demonstrated that 130-gigabaud optical engines lacked the reach required for inter-provincial links, prompting the operator’s research division to target symbol rates exceeding 200 gigabaud. Developing the hardware components necessary to reach 230 gigabaud required two years of laboratory and fabrication work.

For telecommunications operators and cloud infrastructure providers across the Asia-Pacific region, transmission reach determines capital allocation. Trenched fiber remains the most expensive asset in digital networks, frequently requiring years of municipal approvals and civil construction across diverse terrain.

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