Elimination of photoinduced absorption in Ge-doped silica fibres by annealing of ultraviolet colour centres

Heating standard telecommunication Ge-doped silica fibres to 1200 degrees C removes the ultraviolet absorption bands believed to be responsible for photosensitivity. Losses at 480 nm induced by exposure to 249 nm laser light are reduced from 30 dB/m to less than 0.8 dB/m in the annealed fibre.<>