Telecom equipment vendor Huawei and Exatel, a mobile operator in Poland, tested the first 400G WDM (Wavelength Division Multiplexing) system with a single carrier wave on the live network.

This is not the first breakthrough for Huawei in 400G tests.

In June 2012, Huawei and KPN International completed the first 400G field trial in the world.

In December 2012, the Chinese telecom equipment vendor conducted the world’s first 2T field trial with Vodafone, achieving 2 Tbit/s transmission over a distance of up to 3,325 km.

In March 2013, Huawei unveiled a 40T WDM prototype, the highest capacity in the industry, at the OFC/NFOEC2013 event in America.

In a statement, Huawei said the achievement is a significant technical breakthrough in the high-speed transmission field. In the test on the existing G.652-based optical network of EXATEL in Warsaw city, Huawei transmits 400 Gbit/s signals over a single carrier wave.

Currently, the mainstream commercial 40G/100G WDM systems use a single carrier wave. However, on a 400 Gbit/s system, the baud rate doubles, which causes distortion of high-speed signals and unstable clocks. To solve these issues, existing 400G systems use multiple aggregated carrier waves, that is, multiple sub-carrier waves are aggregated to form a super channel.

Huawei adopts the Faster Than Nyquist (FTN) compensation and recovery algorithm, clock recovery technology, and adaptive soft decision FEC (Adaptive-SDFEC) technology, to address the problems of signal distortion and unstable clocks.

Different from a 400G system with multiple aggregated carrier waves, a 400G WDM system with a single carrier wave requires only one optical transceiver system. A 400G WDM system with a single carrier wave is a significant direction for the evolution of customers’ network.

“In order to guide the evolution to the next-generation optical network, Huawei invests a lot on the research of 400G technologies,” said Jack Wang, president of the Transport Network Product Line of Huawei.

Huawei claims that it deployed over 150 commercial 100G networks worldwide.

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