Modeling and Characterization of a Nonblocking $4\times 4$ Mach–Zehnder Silicon Photonic Switch Fabric

We present simulation and experimental results on a silicon photonic strictly nonblocking 4 × 4 electrooptic Mach- Zehnder-based switch fabric. We propose a simulation framework based on the transfer matrix approach that enables calculating the transmission spectra of any type of multistage interconnect switch network. The model is used to analyze the spectral characteristics of the switch fabric. We also show experimental results on a fabric designed and fabricated in IBM's 90-nm photonics-enabled CMOS process. The fabric monolithically integrates the CMOS logic, the switch drivers, and all the photonics. We fully characterized all the transmittances of the switch and demonstrate onchip insertion loss between 1.5 and 3 dB and a crosstalk less than -25 dB for all the signal paths.