The rise of optical interconnects in data centre networks

The exponential increase of Internet traffic due to cloud computing and other emerging web applications has created the need for more powerful data centres. These warehouse-scale data centres consist of thousands of racks interconnected with commodity switches and consume vast amount of energy. To face the requirements of the future data centres, new interconnection schemes have to be adopted to provide high throughput and reduced power consumption. Several optical interconnects for future data centre networks have recently appeared that provide high throughput, low latency and reduced power consumption. This paper discusses the need for a shift of the data centres networks to the optical domain to reduce the power consumption and meet the bandwidth requirements. Additionally, this paper presents some indicative optical interconnects for high performance data centres that have appeared recently in the research literature. Finally, it presents a qualitative categorization and comparison of these schemes based on their main features such as performance, connectivity and scalability.