Optical Switching

14Switch Control: Bridging the Last Mile for Optical Data Centers

Nicola Calabretta¹ and Xuwei Xue²

¹ Electro‐Optical Communication, Eindhoven University of Technology, Eindhoven, Netherlands

² State Key Laboratory of Information Photonics and Optical Communications (IPOC), Beijing University of Posts and Telecommunications, Beijing, China

14.1 Introduction

With the escalation of traffic‐boosting applications, such as cloud computing, Internet of Things, and high‐definition streaming, the bandwidth growth in data centers (DCs) exceeds that of wide‐area telecom networks and even outpaces the bandwidth growth rate of electrical switch application‐specific integrated circuits (ASICs). Due to the technical challenge involved in increasing the pin‐density on the Ball Grid Array (BGA) packaging technique, current electrical switches are expected to hit the bandwidth bottleneck in two generations from now. To overcome the bandwidth bottleneck of electrical switches, switching the traffic into the optical domain has been considerably investigated as a future‐proof solution supplying ultra‐bandwidth. Benefiting from the optical transparency, the optical switch with high bandwidth is independent of the bit rate and data format of the traffic. Moreover, migrating the switching functionality from the electrical to the optical domain removes the power‐consuming optical‐electrical‐optical (O‐E‐O) conversions and eliminates the dedicated electronics circuits for various‐format modulation, ...