Reconfigurable on-chip wireless interconnections through optical phased arrays (Invited)

The realization of on-chip efficient interconnections is one of the most important challenges in developing new computing architectures based on heterogeneous multichip integration. In these architectures, multicore CPUs, GPUs, and memory are densely integrated and need an effective communication layer to exploit their potentialities. In order to overcome the communication bottleneck of these multichip systems, in this work we propose a new approach based on the use of optical wireless switches. These switches can be integrated with an existing Optical Network on Chip as an alternative to ring-based routing matrices with the aim to increase the overall efficiency of the network. In particular, a device allowing on-chip optical wireless interconnections through transmitting and receiving Optical Phased Arrays (OPAs) is presented. In-plane-radiation of simple taper antennas organized as linear antenna arrays is exploited to form 1 x N and N x N switching matrices. The OPAs design criteria are discussed in details and three-dimensional Finite Difference Time Domain (FDTD) simulation results are used to evaluate the performance in term of transmission loss and crosstalk among the different nodes of a 3 x 3 wideband switching fabric.