Dielectric Metasurfaces Enabled Ultradensely Integrated Multidimensional Optical System

Metasurfaces consisted of subwavelength nanostructures can extremely interact with light and manipulate the characteristics of amplitude, phase, and polarization. In particular, on‐chip dielectric metasurfaces have attracted significant attention for optical communication and computing, due to its compact footprint, low loss, and broad bandwidth. Herein, an ultradensely integrated multidimensional optical system with a footprint of only 20 × 30 µm2 based on inverse‐designed dielectric metasurface network, incorporating mode‐division multiplexing, and coherent optical communication technologies that can multiply the system capacity is demonstrated. It is assembled by the ultracompact multifunction on‐chip metasurface devices, including four‐mode demultiplexer, optical hybrid, crossing, and bending, which all have a size of only several micrometers. The inverse‐designed work can significantly broaden the integrated device applications of on‐chip metasurfaces and pave an alternative way for large‐scale high‐capacity optical communication system.