The DREAM: An Integrated Photonic Thresholder

Alexander N. Tait, Bhavin J. Shastri, Mable P. Fok, Mitchell A. Nahmias, Paul R. Prucnal
2013 Journal of Lightwave Technology  
We propose a novel all-optical integrated thresholder called the dual resonator enhanced asymmetric Mach-Zehnder interferometer (DREAM). Unlike prior integrated photonic devices, the DREAM exhibits properties of stable binary decision making, outputting a constant "one" power value for signals above a certain power level and "zero" for signals of lower powers. This thresholding shape arises from the interference of complementary nonlinear effects of two microring resonators (MRR), one in each
more » ... MRR), one in each arm of a Mach-Zehnder interferometer (MZI). The proposed device performs several orders of magnitude better in size, decision latency, energy efficiency, and stability compared to fiber-based methods of optical thresholding. It is best suited for application in densely integrated systems where rapid conversion between analog and digital signal domains is ubiquitous, such as hybrid analog-digital and neuromorphic processing architectures. We derive analytical steady-state solutions to the nonlinear MRR, which enable design simulation, optimization, and automation of a continuous signal thresholder about three orders of magnitude faster than with numerical simulation. Additional numerical simulations indicate the possibility of a 50 GHz pulse thresholder with a 380 pJ switching threshold in a silicon-on-insulator (SOI) platform. The proposed circuit design techniques are potentially applicable to a wide range of materials, waveguide platforms, and resonator types, but for concreteness, we limit the focus of this paper to MRRs in SOI.
doi:10.1109/jlt.2013.2246544 fatcat:ox4ngvifmbfbbaa7i42nr7fnla