Insitu determination of the fiber delay coefficient in time-dissemination networks

High accuracy two-way time transfer systems that use single fiber as a medium, operated bidirectional at dual wavelength, suffer propagation delay asymmetry due to chromatic dispersion. Calibration is necessary for reaching sub-ns accuracies. We present a method to determine and monitor the optical wavelength dependent fiber delay coefficient (α) insitu using the high accuracy time-stamping capabilities of the time dissemination network itself, without the need for an additional fiber link.