title: Ion-exchanged glass binary phase plates for mode-division multiplexing.
abstract: Significant efforts are being made to increase optical network capacity in response to ever-growing data traffic. One promising candidate is mode-division multiplexing (MDM) in few-mode fibers. A fundamental element for MDM is a modal transformer. Modal transformation can be implemented in a free-space basis by using multiregion phase plates. In this work, we show that efficient monolithic binary phase plates can be fabricated by ion exchange in glass and used for MDM tasks. We present an optical characterization method of such plates, which is based on a combination of the inverse Wentzel-Kramers-Brillouin (IWKB) method and Mach-Zehnder interferometric techniques. The IWKB method allows us to design and characterize the phase plates in an easy and fast way, whereas interferometry gives us a precise measurement of the phase step. Far-field optical intensities are measured, and a high-quality mode transformation is confirmed.
authors.affiliation: Departamento de Física Aplicada, Facultade de Física e Facultade de Optica e Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain. carlos.montero@usc.es
authors.forename: Carlos
authors.initials: C
authors.lastname: Montero-Orille
authors.forename: Vicente
authors.initials: V
authors.lastname: Moreno
authors.forename: Xesús
authors.initials: X
authors.lastname: Prieto-Blanco
authors.forename: Eduardo F
authors.initials: EF
authors.lastname: Mateo
authors.forename: Ezra
authors.initials: E
authors.lastname: Ip
authors.forename: José
authors.initials: J
authors.lastname: Crespo
authors.forename: Jesús
authors.initials: J
authors.lastname: Liñares