Nonvolatile programmable Mach-Zehnder meshes

Programmable photonic integrated circuits hold the promise for generic optical circuits akin to the electronic counterpart, such as the widely used field programmable gate array (FPGA) devices. Current programmable photonic integrated circuits are mostly based on power-hungry thermo-optic effects because of their lossless and robust performance. However, thermo-optic effects have also posted significant challenges in terms of energy consumption as well as thermal crosstalk. Here, we present heterogeneous integrated, electrically controlled phase-change silicon photonic Mach-Zehnder mesh circuits, which render zero-static power, little crosstalk as well as great programmability. These include both circulated mesh structures and forward-only self-aligning architecture. Our work shows the great capability and advantage of phase-change materials in programmable photonic integrated circuits and hence presents a significant step toward truly set-and-forget programmable photonic integrated circuits.