Photopatternable fluorinated poly(arylene ether ketone) for optical waveguide devices

Fluorinated poly(arylene ether)s are attractive for the fabrication of optical waveguide devices for photonic applications due to their low optical attenuation and high thermal stability. A variety of waveguide devices have been fabricated in these polymers through thermal crosslinking followed by a reactive ion etch process. This work reports on the use of a novel fluorinated poly(arylene ether ketone) incorporating tetrafluorostyrol groups for photo-crosslinking. This new molecular design allows sufficient photosensitivity to fabricate waveguides through a UV direct patterning and wet-etch method, offering a fast, convenient and economic approach to making polymer photonic devices. Data concerning the polymer molecular structure and choice of suitable photo-initiators for the fabrication of the devices are presented in this paper. Based upon the optical and thermal properties of the resultant materials it appears that similar degrees of polymer crosslinking can be achieved using the photo-curing process as those using a thermal crosslinking process. High quality waveguide devices with smooth, well-defined sidewalls are demonstrated. Optical characterization of these devices suggests that the waveguide quality is comparable to that of waveguides fabricated using a dry etch process.