Numerical and experimental demonstration of inverse designed low-index polarization-insensitive wavelength demultiplexer

The computational inverse design has paved the way for of highly efficient, compact, and novel nanophotonic structures beyond human intuition trial-and-error approaches. Apparently, with power, exploration implementation multi-objective, complex, functional devices become feasible. Herein, we used a recently emerged framework to demonstrate 1 × 2 polarization-insensitive wavelength division multiplexer (PIWDM) made low-refractive-index material an index 1.55. inversely designed PIWDM structure successfully steers toward targeted channels 1.30 μm 1.55 TE TM polarizations. Taking advantage low refractive material, scaled structural dimensions corresponding microwave region, fabricated compact device using 3D printer, conducted experiment as proof concept. With crosstalk values less than -11.45 dB, transmission were -2.42 -2.18 dB -2.19 -2.23 polarization at upper lower waveguides, respectively.