Effects of doping concentrations on the regeneration of Bragg gratings in hydrogen loaded optical fibers

The fabrication and optimization of regenerated Bragg gratings (RBGs) in hydrogen loaded single mode optical fibers (SMF) are presented. In addition to standard Ge-doped SMF, two kinds of B–Ge codoped SMFs with different doping concentrations are prepared using plasma-activated chemical vapor deposition (PCVD) technique to fabricate RBGs. The effects of doping concentrations on the dynamics of grating regeneration and the thermal stability of RBGs are experimentally investigated. The reflectivity of RBGs with length of 10 mm was enhanced from 20% to 40% through the optimization of doping concentrations. All fabricated RBGs can sustain in high temperature up to 1000 °C.

Research Highlights
► The effects of doping concentrations on the dynamics of grating regeneration are investigated.
► Increase of the doping concentration of Ge will bring some significant effects on RBGs: 1) lower the erasure temperature; 2) increase the refractive index modulation; 3) decrease the thermal stability.
► The fabricated RBGs can sustain in high temperature up to 1000 °C.