Recycling forward and backward frequency multiplexed modes in a waveguide coupled to phased time perturbed microrings for low footprint neuromorphic computing

Optical structures can serve as low-power high-capacity alternatives of electronic processors for more efficient neuromorphic computing, but can suffer from large footprints and weak scalability. In this work, properly phased time-perturbed microrings side-coupled to a waveguide are utilized to realize a compact processor for linear transformations. We build up a synthetic frequency dimension to provide sufficient degrees of freedom, where the linear time-varying structures enable the linear intermixing and transformation of frequency-multiplexed data. Moreover, non-reciprocal and asymmetric flow of data in the forward and backward modes, due to phasing of the perturbations, helped to build up another synthetic dimension and to avoid physically repeating the processing elements, thus enabling a much more compact and scalable linear processor.