Polymer gratings achieved by focused ion beam

As part of the development of polymer-based devices in the field of lightwave technology, a method for the implementation of gratings etched in PMMA and fluorinated polyimide using focused ion beam (FIB) technology is reported. The interest for these devices results from the fact that diffractive optical elements (DOEs) provide elegant answers to the wave-division-multiplexing (WDM) technique. More precisely surface relief gratings (SRGs) are of high interest at the stage of wavelength demultiplexing. We will present three kinds of gratings, echelon grating, crossed gratings and gratings with circular apertures. tire processing method is exposed. Ion irradiation parameters and time of exposition are reported. The design parameters are entirely driven by a computer. All these parameters are studied in relation with the polymer nature. The limitations in microfabrication are presented, of course as a function of the polymer, but also as a function of the film coating process.