WDM-enabled multi-core parallel programmable photonic signal processor

As a frontier in integrated photonics, 2D waveguide mesh-based programmable processors offer compact, reconfigurable platforms. However, conventional Mach-Zehnder interferometer (MZI)-based designs rely on wavelength-agnostic routing, which monopolizes the entire mesh for a single functionality at a time, leaving the wavelength domain untapped and bottlenecking parallel processing. Here, we demonstrate a wavelength-division multiplexing (WDM)-enabled multi-core parallel programmable photonic processor using a reconfigurable hexagonal mesh. Our architecture utilizes MZIs integrated with over-coupled microring resonators as wavelength-selective phase shifters. Exploiting sharp phase transitions, these units achieve 1 THz free spectral range and 4.3 mW/π tuning power. By synergistically integrating spatial and wavelength degrees of freedom, our processor allows a single mesh to host distinct network configurations simultaneously. This enables multi-threaded execution and enhanced functional density, demonstrated through flex-grid WDM, parallel optical computation, and microwave photonic dual-beamforming. This work establishes WDM-enabled processing as a promising route toward large-scale, highly parallel integrated photonic systems.