Huawei says it will provide equipment for a 400-Gbps WDM network based on a proprietary Optical Transport Network (OTN) scheme while separately it has demonstrated single-carrier 400G optical transmission using advanced signal processing techniques.
Huawei is delpoying the 400G WDM metro network technology for Telefonica Chile to interconnect data centres in Santiago and support the roll out of IPTV and LTE cellular services. The project will include the Chinese vendors 100G coherent technology as well as 16-QAM to achieve 400G transport, combined with a proprietary OTN scheme.
OTN is a framing scheme, defined by the International Telecommunication Union, to transport, multiplex, switch and manage signals. OTU4 is the fastest signalling scheme defined to date, and at 112Gbps is fast enough to support 100 Gigabit Ethernet. However, while work is ongoing to define the next speed increment, there is no OTN specification for 400 Gbps.
Orange has already deployed a 400G link in its network using 16-QAM technology from Alcatel-Lucent, but Huawei claims its scheme is the first to use 400G OTN technology. OTN equipment supporting the next ITU specification will likely become available in 2015 at the earliest, the vendor says.
In a separate announcement, Polish operator EXATEL and Huawei demonstrated 400G optical transmission. Unlike the Telefonica Chile deployment that uses two carriers, each carrying a 16-QAM signal, Huawei transmitted the 400G signal using a single optical carrier.
Transmitting 400Gbps over a single carrier requires a doubling of the baud rate. To achieve single-carrier 400Gbps while relaxing the baud rate, Huawei has adopted a faster-than-Nyquist sampling and signal recovery scheme, proprietary clock recovery technology, and adaptive soft-decision forward error correction.
Using a single-carrier approach simplifies the management of wavelengths for an operator and there are also system benefits in terms of capacity and power improvements, says the vendor.
By Roy Rubenstein
Press release: Huawei and Telefonica Chile to Deploy the World’s First OTN-based 400G WDM Network
Press release: EXATEL and Huawei Successfully Test the First Single Carrier 400G WDM System