This chapter discusses the rise of optical interconnection networks in cloud computing infrastructures as a novel alternative to current networks based on commodity switches. Optical interconnects can significantly reduce the power consumption and meet the future network traffic requirements. Additionally, this chapter presents some of the most recent and promising optical interconnects architectures for high performance data centers that have appeared recently in the research literature. Furthermore, it presents a qualitative categorization of these schemes based on their main features such as performance, connectivity, and scalability, and discusses how these architectures could provide green cloud infrastructures with reduced power consumption. Finally, the chapter presents a case study of an optical interconnection network that is based on high-bandwidth optical OFDM links and shows the reduction of the energy consumption that it can achieve in a typical data center.