Fast optical switching technologies for inter/intra data center networks

The continuous evolution of data centers (DC's) has fueled a relentless growth of burst-mode (BM) traffic. DC networks have long relied on electrical switching, but the mismatch between optical transmission and electrical switching has become a bottleneck for DC networking. Optical switching, with related BM technologies, can play a pivotal role in overcoming this issue. For intra-DC networks, switching on a packet-by-packet basis requires optical switches with fast re-configurability in the order of nanoseconds. We discuss the requirements these switches have to satisfy and highlight the tradeoffs in their implementations by reviewing three different types of optical switches we have developed; namely a wavelength-based routing switch (WRS) comprising fast tunable laser diodes (TLD) and an arrayed waveguide grating (AWG), a broadcast-and-select (B&S) switch based on electro-absorption modulators (EAMs), and a route-and-select (R&S) switch combining Mach-Zehnder interferometers (MZIs) and EAMs. On the other hand, apart from warehouse-scale DC networks, the pressing demand for reducing data transmission latency has been promoting the distribution of smaller DCs in the metro segment of optical transport networks. We address this demand by proposing the realization of a dynamic and highly scalable inter-DC network based on BM optical switching technologies, and highlight the role of fast space/wavelength switching to fulfill this goal.