Ultra-broadband mode converter and multiplexer based on sub-wavelength structures
D. González-Andrade, J. G. Wangüemert-Pérez, A. V. Velasco, A. Ortega-Moñux, A. Herero-Bermello, I. Molina-Fernández, R. Halier, P. Cheben IEEE Photonics Journal. 2018.