Nanofabrication and test of novel diffractive optics for OAM-mode division multiplexing in optical fibers

The orbital angular momentum (OAM) of light offers a promising solution to today's overwhelming demand of bandwidth and has known an increasing attention as a new degree of freedom in the telecom field. Here we present the design, fabrication and optical characterization of miniaturized phase-only diffractive optical elements (DOE) for OAM beams generation, multiplexing and sorting. Samples have been fabricated with high-resolution electron-beam lithography and exhibit high fabrication quality. Different DOE designs are presented for the sorting of optical vortices with different steering geometries in far-field and applications in free-space and optical fibers.