In recent years, mode-division multiplexing (MDM) has been proposed as a
promising solution in order to increase the information capacity of optical
networks both in free-space and in optical fiber transmission. Here we present
the design, fabrication and test of diffractive optical elements for
mode-division multiplexing based on optical transformations in the visible
range. Diffractive optics have been fabricated by means of 3D high-resolution
electron beam lithography on polymethylmethacrylate resist layer spun over a
glass substrate. The same optical sequence was exploited both for input-mode
multiplexing and for mode sorting after free-space propagation. Their high
miniaturization level and efficiency make these optical devices ideal for
integration into next-generation platforms for mode-division (de)multiplexing
in telecom applications.Comment: 4 pages, 1 extended references page, 6 figures. arXiv admin note:
substantial text overlap with arXiv:1610.0744
