Microwave Photonics Filters Using a Silicon Nitride Programmable Processor with Folded Heaters

Programmable photonic processors rely on the large-scale integration of beamsplitters and reconfigurable phase shifters, distributed within unit cells or photonic gates. In this work, we present a unit cell topology design to increase the integration density of waveguide mesh arrangements. We report the design details of a 40-unit cell waveguide mesh integrated in silicon nitride. The chip is electrically interfaced to a PCB and we report its characterization and examples of basic microwave photonic filters.