Scalable Multilayer Architecture for General Optical Transformation Matrix

This paper introduces a method for general N mode transformation of light using multilayer interferometers, reducing the number of phase-shifter layers from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2\mathrm{N}+3$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{N}+2$</tex>. We show numerically that simple constant-depth mixing layer exhibits error-tolerance. © 2024 The Author(s)