Motivation: In modern medical procedures, flexible tools, catheters, and endoscopic devices are commonly used. Despite several advantages over conventional instruments, they still suffer from a lack of real-time feedback on their shape. Fiber Bragg grating(FBG)-based 3D shape sensing is a promising approach as it is small, immune to electromagnetic noise, sterile, and easy to replace. Working Principle: FBGs are some periodic patterns of different refractive indices inside the core of an optical fiber. They show large reflectivity around Bragg wavelength, which is sensitive to mechanical and thermal perturbations.