Organic-inorganic metal halide glass optical fibers for ultralow-loss and bendable photonic applications

Organic-inorganic metal halides (OIMHs) exhibit remarkable thermodynamic transitions between crystalline and amorphous states, yet their potential application in optical fibers has not been explored. In this study, we present a melt-filling strategy leveraging the low-temperature (230°C) fluidity of (HTPP) 2 MnBr 4 and (HTPP) 2 SbBr 5 (HTPP = hexyltriphenylphosphonium) glasses to fabricate optical fibers with controllable diameters and lengths. These OIMH fibers processed at 230°C feature a core-cladding structure with minimal defects, achieving remarkably low transmission losses of 0.41 dB/cm for Mn-based fibers and 0.16 dB/cm for Sb-based fibers, along with exceptional mechanical flexibility (bending radius ≤0.8 mm). These optical fibers enable information encryption systems and reliable light transmission under bending, demonstrating their potential applications in optical encryption and integrated photonics. This work establishes OIMHs as promising candidates for next-generation optical waveguides.