In the last two decades, Fiber Bragg Grating (FBG) sensor were been widely studied and employed in temperature and strain sensing application. Due to their high potentiality in term of radiation hardness and EMI insensitivity, they constitute the ideal device to operate in harsh environments, under ionizing radiation and strong magnetic fields. This thesis work is focused on the research, development and simulation of novel sensors and monitoring systems suitable to operete in these environmental conditions.In particular, the monitoring applications regards room temperature of Compact Muon Solenoid (CERN), cryogenic temperature (up to 4.2 K) of the powerful cooling system of the LHC's superconducting magnets, and magnetic field with magnetostrictive and magneto-optic approaches
