Mode Multiplexer Based on Multiplane Light Conversion Using a Monolayer Metasurface

We propose a mode-division multiplexer based on multiplane light conversion (MPLC) using a monolayer-structured metasurface and a reflective half-wave plate (HWP). A monolayer metasurface can impose two independent wavefront modulations to the fiber output waves. Our design releases the need for strict phase plate alignment in the MPLC experiments.