Accurate Self-Configuration of Rectangular Multiport Interferometers

Understand

Multiport interferometers based on integrated beamsplitter meshes are widely used in photonic technologies.

• While the rectangular mesh is favored for its compactness and uniformity, its geometry resists conventional self-configuration approaches, which are essential to programming large meshes in the presence of fabrication error.
• Here, we present a new configuration algorithm, related to the $2\times 2$ block decomposition of a unitary matrix, that overcomes this limitation.
• Our proposed algorithm is robust to errors, requires no prior knowledge of the process variations, and relies only on external sources and detectors.