Single-Mode-Fiber Design for Low Latency and Low Loss

Low-latency transmission is necessary for optical transmission systems, and a reduction in propagation delay of 1 μs in an optical fiber is effective. We investigated the tradeoff between latency and loss among silica-glass solid-core optical fibers. The decreases in the core radius and core refractive index are known to reduce group delay of pure silica core fibers. We experimentally evaluated the Rayleigh-scattering-loss and imperfection-loss characteristics of pure silica core fibers with smaller radius and fluorine (F)-doped core fibers. A decrease in the pure-silica-core radius has a non-negligible impact on imperfection-loss increase compared with on Rayleigh-scattering-loss increase induced by F-doped core and clad. We show the potential of F-doped core designs for reducing propagation delay of 1 μs after an over 500-km long transmission while suppressing the impact on loss increase.