Dielectric Broadband Metasurfaces for Fiber Mode-Multiplexed Communications

A subwavelength-thick spatial-mode multiplexer based on a highly transparent all-dielectric Mie-resonant metasurface is demonstrated with a broadband response covering major optical communication wavelength bands. The metasurface is employed to convert simultaneously each orthogonal polarization of LP₀₁ inputs into individual higher-order TM₀₁ and TE₀₁ vectorial modes, without the need of a polarization diversity setup. This is not feasible using current mode multiplexing approaches. An LP₀₁ polarization-multiplexed 51 × 64 quadrature amplitude modulation (QAM) superchannel, with a 10.3 bits s⁻¹ Hz⁻¹ spectral-efficiency and total bit-rate of 13.2 Tb s⁻¹, is converted to higher-order modes with the metasurface multiplexer, and then mode-multiplexed data is transmitted over a multimode fiber. The results demonstrate the potential application of these metadevice-based mode multiplexers in space-division multiplexed systems.