Ciena’s latest coherent DSP-ASIC, the WaveLogic Ai, follows on from the company’s WaveLogic 3 family of coherent chips that was first announced in 2012. The WaveLogic Ai silicon will be used in Ciena’s systems from the second quarter of 2017.
The WaveLogic Ai chipset includes such features as real-time network monitoring that makes network measurement data available every 10ms. The data can be fed through application programming interfaces to analytics software whose output will be used by operators to adapt their networks.
“We do believe we are taking that first step towards a more automated network and even laying the foundation for the vision of a self-driving network,” said Helen Xenos, director, portfolio solutions marketing at Ciena.
The WaveLogic Ai also supports two baud rates: 35 gigabaud and 56 gigabaud. The lower baud rate is one used by current optical transmission systems. The baud rate is suited to existing fixed-grid networks based on 50GHz-wide channels. At 35 gigabaud, the WaveLogic Ai supports data rates from 100Gbit/s to 250Gbit/s.
The second, higher 56-gigabaud rate enables 400Gbit/s single-wavelength transmissions and supports data rates spanning 100Gbit/s to 400Gbit/s in increments of 50Gbit/s.
For a 200Gbit/s transmission using 35-gigabaud and 16-QAM, effectively 8 bits per symbol are sent. In contrast, 5 bits per symbol are used with the faster 56-gigabaud rate. Here, a more complex modulation scheme is employed based on multi-dimensional coding. Such higher-dimension formats may use more than one time slot, or sub-carriers in the frequency domain, or both techniques.
At 56 gigabaud, Ciena says the reach at 200Gbit/s is 3,000km, a threefold improvement compared to operating at 35 gigabaud and 16-QAM. Overall, the WaveLogic Ai enables submarine links of 14,000km at 100 Gbit/s, 3,000km links at 200Gbit/s, as detailed, 1,000km at 300Gbit/s and 300km at 400Gbit/s.
Other Ai features include support for 400 Gigabit Ethernet and Flexible Ethernet. Flexible Ethernet helps line cards match the client signals to the variable line rates.
By Roy Rubenstein