All-optical processing in switching networks

In the backbone of today’s high performance networks, optical fibers provide enormous point-to-point communications capacity. With the deployment of DWDM equipment, aggregate throughputs on the order of a few Tbps per fiber are being achieved [1]. However, despite the recent success of fiber optics, it has so far been used primarily as a low loss, high bandwidth replacement to electrical cable in point-to-point transmission links. In these systems, optical signals are usually converted to the electrical domain at intermediate nodes in order to perform switching and signal processing. For example, in the Internet, electronic switches are used to route packets to their destinations. However, in this approach, the maximum serial line rate is limited by the bandwidth of electronics, which is considerably less than the bandwidth available in optical fiber. In effect, an “electronic bottleneck” is created in the system. This article summarizes the research efforts at Princeton University towards the development of network nodes capable of all-optical signal processing and routing.