Liñares Beiras, JesúsPrieto Blanco, XesúsMoreno de las Cuevas, VicenteMontero Orille, CarlosMouriz Cereijo, María DoloresNistal Fernández, María ConcepciónBarral Raña, David2020-06-012020-06-012017Jesús Liñares, Xesús Prieto-Blanco, Vicente Moreno, Carlos Montero-Orille, Dolores Mouriz, María C. Nistal, and David Barral, "Interferometric space-mode multiplexing based on binary phase plates and refractive phase shifters," Opt. Express 25, 10925-10938 (2017)http://hdl.handle.net/10347/22753A Mach-Zehnder interferometer (MZI) that includes in an arm either a reflective image inverter or a Gouy phase shifter (RGPS) can (de)multiplex many types of modes of a few mode fiber without fundamental loss. The use of RGPSs in combination with binary phase plates for multiplexing purposes is studied for the first time, showing that the particular RGPS that shifts π the odd modes only multiplexes accurately low order modes. To overcome such a restriction, we present a new exact refractive image inverter, more compact and flexible than its reflective counterpart. Moreover, we show that these interferometers remove or reduce the crosstalk that the binary phase plates could introduce between the multiplexed modes. Finally, an experimental analysis of a MZI with both an approximated and an exact refractive image inverter is presented for the case of a bimodal multiplexing. Likewise, it is proven experimentally that a RGPS that shifts π/2 demultiplexes two odd modes which can not be achieved by any image inverter.eng© 2017 Optical Society of America. Open Access. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reservedjournal article10.1364/OE.25.0109251094-4087open access