In a hermetically sealed package of waveguide devices, optical fibers are bonded to the waveguide terminal with resin adhesive materials. Here, a recently developed commercial epoxy-based, ultraviolet-radiation-curable adhesive material with a low refractive index of 1.46 is evaluated for such a purpose where chemical and mechanical stability and reliability are greatly demanded. The results show this adhesive material exhibits reliable bonding characteristic for the fiber and Ti:LiNbO3waveguide with high chemical stability, indicating its possible application in packaged components for optical communication systems.