Huawei touts 400G WDM prototype

Huawei Technologies Co. Ltd. is talking about its new 400G WDM prototype for ultra-long-haul optical transmission at OFC 2014. The prototype employs what the company calls “faster than Nyquist” (FTN) technology to increase the 400G transmission distance beyond 3000 km. This represents a significant breakthrough in high-speed WDM transmission, according to the Chinese vendor.

The Nyquist sampling theorem defines a maximum transmission speed for a fixed channel bandwidth. By utilizing spectrum compression and signal distortion compensation algorithms, FTN technology achieves long-haul transmission of high baud-rate signals on existing networks. The vendor likens the technology to data compression, allowing more data to be transmitted than the bit rate would suggest.

Huawei has applied the technology to two types of 400G transmission using 100-GHz channel spacing — a short-haul solution and the ultra-long-haul solution unveiled at OFC 2014.

The short-haul solution, which applies to metropolitan area network transmission, adopts single-subcarrier polarization-division-multiplexed 16 quadrature amplitude modulation (1SC-PDM-16QAM), which allows high-quality 400G transmission over a single carrier wave. Huawei's single-carrier 400G solution was recently tested on EXATEL's live network in Poland (see “EXATEL trials Huawei single-carrier 400G WDM platform”).

The ultra-long-haul solution, which applies to backbone transmission, adopts dual-subcarrier polarization-division-multiplexed quadrature phase-shift keying (2SC-PDM-QPSK) modulation and supports a record transmission distance of over 3000 km.

"Huawei has been investing heavily in the high-speed WDM field. The new FTN technology introduced in the prototype exceeds traditional technological limits to deliver ultra-long-haul 400G transmission, breaking new ground for the 400G industry," said Jack Wang, president of Huawei’s transmission network product line.

In addition to the trial with EXATEL, Huawei is claiming several other industry firsts in high-speed transmission. In June 2012, Huawei and KPN International completed the world's first pan-European 400G field trial. In December 2012, Huawei conducted the world's first 2T field trial with Vodafone, achieving 2-Tbps transmission over a distance of 3,325 km (see “Huawei tests 2 Tbps superchannels over Vodafone’s network”). Last year at OFC 2013, Huawei unveiled a 40T WDM prototype ("Huawei prototypes 40-Tbps WDM system").

Huawei says the 400G WDM prototype unveiled at OFC 2014 again demonstrates that operators' installed optical network infrastructure has the potential to achieve ultra-long-haul transmission of 400-Gbps or even 1-Tbps signals.

For more information on high-speed transmission systems and suppliers, visit the Lightwave Buyer’s Guide.

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