Considerable experience has been gained using optical fibre cables in terrestrial and subsea applications showing that optical fibres provide a stable transmission medium. There are some situations where the concentration of hydrogen within a cable can rise to a sufficiently large value to cause the optical loss of the fibre to increase (see Appendix III). Therefore, there is a need to determine the build-up of hydrogen in a cable by considering the ways that hydrogen can be generated within it.If the escape of hydrogen through the polyolefin sheath or the overlap of a moisture barrier balances the hydrogen generated in the cable, the resulting concentrations within the cable do not cause a noticeable change in optical loss.
ITU-T L.27 FRENCH-1996 history
1996ITU-T L.27 FRENCH-1996 Method for Estimating the Concentration of Hydrogen in Optical Fibre Cables