This paper addresses the development of superstructure fiber Bragg gratings (FBGs)by laser-assisted direct writing of on-fiber metallic films. A novel laser directwrite method is characterized to fabricate periodic films of silver nanoparticles onthe non-planar surface of as-fabricated FBGs. Silver films with a thickness of9 µm are fabricated around a Bragg grating optical fiber. The performance of the superstructureFBG is studied by applying temperature and tensile stress on the fiber. Anopto-mechanical model is also developed to predict the optical response of the synthesizedsuperstructure FBG under thermal and structural loadings. The results show that thereflectivity of sidebands in the reflection spectrum can be tuned up to 20% and 37%under thermal and structural loadings, respectively. In addition, the developedsuperstructure FBG is used for simultaneous measurement of force and temperature toeliminate the inherent limitation of regular FBGs in multi-parameter sensing.