Summary - G.681 (11/2025) - Distributed fibre optic sensing system for terrestrial optical transmission systems

Recommendation ITU-T G.681 specifies the distributed fibre optic sensing (DFOS) optical interface requirements for implementing DFOS within terrestrial optical transmission systems. Optical interface requirements include DFOS wavelength allocation, interference and allowable crosstalk between the channel(s) of the optical transmission system and the DFOS channel(s). The sensing fibre is an optical fibre used by the optical transmission system.