Precise life-time prediction using demarcation energy approximation for distributed activation energy reaction

The requirement from the industry of precise lifetime estimation of Bragg gratings in optical fibres and other optical devices motivated us to perform calculations in a region of a master curve (describing the time evolution of a system at any temperature) where an approximation, called demarcation energy, is no longer valid. We describe a correction procedure that leads to reintroducing afterwards a temperature dependence lost in this approximation while preserving most of the advantages of the demarcation energy approach. With our procedure, a precise determination of burning-in parameter for achieving lifetime specification is possible. A Bragg grating written in H-2 loaded Ge doped silica core optical fibres is used as application example.