ИСТИНА

Photonic information processing often demands programmable multiport interferom- eters capable of implementing arbitrary transfer matrices, for which planar meshes of tunable Mach-Zehnder interferometers (MZIs) are usually exploited [1], [2]. However, these MZI-based interferometers require balanced static beam-splitter (BSs) that make them sensitive to manufacturing errors. Here, we abandon the error-sensitive MZI and propose an alternative design that uses a single static BS and a variable phase shift as the building block of the interferometer mesh. Our BS-based design [3] (wich strongly utilizes the ideas in [4]) has been shown to possess superior resilience to manufacturing errors, which is achieved without addition of extra elements into the schemes. Namely, the power transmissivities of the static BSs constituent the interferometers can take arbitrary values in the range from ≈ 1/2 to ≈ 4/5.