Inverse design of a fiber-to-fiber integrated metasurface system for multiplexing and demultiplexing of orbital angular momentum modes
Year: 2026
Type: article
Abstract: A two-way multiplexer (MUX) and demultiplexer (DEMUX) system to separate spatially overlapping OAM modes in a multi-mode fiber into spatially separated Gaussian modes in a multi-core fiber has been designed and modelled. The designed system consists of two silicon metasurfaces. Each metasurface consists of silicon nanopillars with spatially varying radii arranged on a square grid. These metasurfaces were simulated as if they were placed on the facets of the two optical fibers under consideration, spaced at a suitable distance, face-to-face. The metasurfaces are designed using a gradient-based inverse design approach that yields an optimized spatial distribution for the radius of each nanopillar, and the functionality is verified through full-wave simulations. The system can handle a set of six OAM modes with topological charges l = ( ± 20, ± 30, ± 40). The average single-mode fiber-to-fiber insertion loss (IL) at 1550 nm was 8.99 dB when using the system as a MUX and 6.30 dB when used as a DEMUX, respectively. The average crosstalk was -17.8 dB in MUX operation and -17.7 dB in DEMUX operation, respectively. Our approach opens a pathway to compact and highly efficient mode-division multiplexing architectures, enabling next-generation high-capacity optical communication systems and inspiring further advances in metasurface-based fiber-interfacing technologies.
Source: Optics Express
DOI: 10.1364/oe.617888
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W7221476235