High-spatial-resolution distributed Brillouin sensing in plastic optical fibers: detection of 5cm heated region

We propose and experimentally validate a strategy to enhance the spatial resolution of Brillouin optical correlation-domain reflectometry (BOCDR) in perfluorinated graded-index plastic optical fibers (POFs). By precisely accounting for the refractive index mismatch between silica and plastic fibers, we derive an optimized modulation amplitude that exceeds the conventional limit imposed by Rayleigh noise. Using this approach, we successfully detect a 5.0-cm heated section along a POF at a nominal spatial resolution of 4.4 cm, representing the highest value reported to date.