In this paper we investigate the fiber Bragg grating (FBG) arrays selectively inscribed in a multicore fiber for a different sensor and laser applications. Particularly, wavelength-switchable and tunable fiber laser was realized based on uniform and non-uniform FBGs precisely positioned in the selected cores. A quasi-distributed 3D shape sensor based on FBG array inscribed in a multicore fiber with helically twisted side cores was fabricated and applied for shape reconstruction of papillotome.