Fabrication and characterization of ion-exchanged glass binary phase plates for mode-division multiplexing

In response to ever growing data traffic, significant efforts are being made to increase optical network capacity. One promising candidate is mode-division multiplexing (MDM) in few-mode fibers, which uses space as a new information-bearing dimension. A fundamental element for MDM is a modal transformer. Modal transformation can be implemented in a free-space basis by using multi-region phase plates. In this work we present the design, fabrication and characterization of monolithic binary phase plates by highly-uniform Ag+/Na+ ion-exchange in glass. Diffracted optical field intensities have been measured and high quality mode transformation has been confirmed.