Geometric optics analysis of inverted graded index fibers

We derive a general solution based on geometric optics that describes the light propagation properties in multimode optical fibers with inverted refractive index profiles. Using this general solution, we classify rays according to their propagation properties and calculate the analytical expressions of the ray trajectories inside these fibers under different launching conditions. In addition, we discuss the most suitable propagation conditions that maximize the confinement of light power in the vicinity of the core-cladding interface for sensing purposes.hese results are part of the Grant Nos. PID2021-122505OB- C31, TED2021-129959B-C21 and PDC2022-133053-C21, funded by MCIN/AEI/10.13039/501100011033, by ‘ERDF A way of making Europe’ and by the ‘European Union Next GenerationEU/PRTR’, and also of the Grant Nos. IT1452-22, ELKARTEK KK 2021/00082 and ELKARTEK KK 2021/000 funded by the Gobierno Vasco/Eusko Jaurlaritza