Photosensitive terpolymer for all-wet-etching process: Material characterization and device fabrication

A photosensitive terpolymeric composition suitable for practical waveguide devices is provided. The terpolymer was produced from pentafluorostyrene, perfluoro-n-octyl acrylate, and glycidyl methacrylate. We present a fabrication process where the device structure utilizes the same class of material for the core and cladding layers and it was fabricated without a plasma etching process. Based on the developed material and process; a 16-channel arrayed waveguide grating with good performance has been realized. During temperature cycling, a slight thickness hysteresis and refractive index hysteresis was observed above the glass transition temperature and is ascribed to the fact that the terpolymer material may not completely recover its elasticity in the heating/cooling cycle.