Modular AWG-based Interconnection for Large-Scale Data Center Networks

Along with the recent surge in scale expansion of data centers, the interconnection scheme is facing a grave challenge. A huge amount of cables between the switches make the system maintenance and heat dissipation extremely difficult. A promising solution to this problem is using the arrayed waveguide grating (AWG), which can provide a set of wavelength links between its inputs and outputs. However, the scalability of the AWG-based interconnection scheme is restricted by the coherent crosstalk and the wavelength granularity of AWGs. In this paper, we propose a generic modular AWG-based interconnection scheme with scalable wavelength granularity for mega data centers. We first devise a matrix-based method to decompose the AWG into a three-stage network of smaller AWGs, while preserving the nonblocking wavelength routing property of the AWGs. We then introduce the concept of wavelength independency based on the partitioning of the optical connections, such that modular AWGs in the network can reuse the same wavelength set with smaller granularity. We show that the proposed modular AWG-based interconnection network can simplify the cabling complexity of data center networks, while preserving the same function and bandwidth as the original data center network.