The exponential growth of global internet traffic creates significant challenges for both data centre operators and equipment manufacturers. As the use of increasingly complex cloud-based applications, social media and big data analytics continues to increase, these challenges will only intensify. To handle this traffic, data centres currently utilise hundreds of thousands of servers arranged in several hierarchical layers, each of which requires a low-cost and energy-efficient interconnected network. Furthermore, the switching platforms that these servers use must support the high bandwidth required for large-scale, non-blocking topologies. The fact is that the conventional electronic packet switching and copper-based interconnection technologies used to meet these requirements consume a lot of power, have limited reach and are trending towards increasing latency. One potential solution is photonic technologies, which have been shown to significantly enhance the performance of data centre servers. Unfortunately, as the development of such technologies remains in its infancy, increasing traffic requirements far outpace current capabilities. To help bridge this gap between traffic and technology, the EU-funded L3MATRIX (Large Scale Silicon Photonics Matrix for Low Power and Low Cost Data Centers) project has developed the next generation of data centre infrastructure. “By providing a new method for building switching elements for data centres, we can reduce costs and increase efficiency and performance,” says Tolga Tekin, L3MATRIX project coordinator. “The result will be the building of large networks offering petabyte per second (PB/s) speeds and thus the ability to handle the internet traffic of tomorrow.”
A radically new system
The key innovation behind the L3MATRIX project is a new method for building switching elements. By co-packaging the optical interconnects with the switching application-specific integrated circuit (ASIC), researchers were able to increase the chip radix – the main barrier to bandwidth scaling. The optical interconnect is implemented as a large, two-dimensional silicon photonics matrix, which, as a single-mode optical solution, provides both the required data density and long-reach. Packet parsing and switching is then assigned to the ASIC. The outcome of this long-reach photonic-digital integration is a radically new system and network architecture. With the L3MATRIX, data centres will be able to scale their network to PB/s speeds using just a fraction of the devices that would otherwise be needed. “This is an innovative method for building switching elements that are both high radix and have an extended bandwidth of 25 gigabits per second (Gb/s) in single mode fibres and waveguides with low latency,” explains Kobi Hasharoni, the project’s technical manager. “When a data centre integrates these devices into its network, the result will be a 10-fold decrease in power consumption compared to conventional technology.” The L3MATRIX system also reduces latency into the 10 to 20 nanosecond range. This is because the number of networking (hops) that a packet needs to make is smaller as the network deploys fewer switching layers.
The natural evolutionary step
According to Tekin, the on-chip assembly of the optical interconnect transceiver is a natural evolutionary step in the optical interconnect industry: “The L3MATRIX project successfully demonstrated the basic building blocks of a co-packaged optical system. This technology platform is now available to small and medium-sized enterprises to further develop and integrate into the infrastructure that will power the data centres of tomorrow.”
L3MATRIX, data centre, co-packaging, optical intercepts, internet, social media, big data, servers, photonic technologies, switching elements