title: Chromatic characterization of ion-exchanged glass binary phase plates for mode-division multiplexing.
abstract: Mode-division multiplexing (MDM) in few-mode fibers is regarded as a promising candidate to increase optical network capacity. A fundamental element for MDM is a modal transformer to LP modes which can be implemented in a free-space basis by using multiregion phase plates, that is, LP plates. Likewise, several wavelengths have to be used due to wavelength multiplexing purposes, optical amplification tasks, and so on. In this work we show that efficient monolithic binary phase plates for different wavelengths can be fabricated by ion-exchange in glass and used for MDM tasks. We introduce an optical characterization method of the chromatic properties of such phase plates which combines the inverse Wentzel-Kramers-Brillouin (IWKB) together with Mach-Zehnder and Michelson-based interferometric techniques. The interferometric method provides a measurement of the phase step for several wavelengths, which characterizes the chromatic properties of the phase plate. Consequently, it is shown that the IWKB method allows us to design and characterize the phase plates in an easy and fast way.
authors.forename: Xesús
authors.initials: X
authors.lastname: Prieto-Blanco
authors.forename: Carlos
authors.initials: C
authors.lastname: Montero-Orille
authors.forename: Vicente
authors.initials: V
authors.lastname: Moreno
authors.forename: Eduardo F
authors.initials: EF
authors.lastname: Mateo
authors.forename: Jesús
authors.initials: J
authors.lastname: Liñares