Temperature-insensitive long-period fiber gratings written in P 2 O 5 co-doped GeO 2 -SiO 2 core optical fibers

Here we report the possibility of phosphorus oxide (P205) as another candidate for a negative thermal coefficient material. Longperiod fiber gratings were successfully fabricated in P205 co-doped Ge02-SiO2 fibers employing a 193- nm ArF excimer laser, and it has been clarified that P205 is available for suppressing the thermal sensitivity of the gratings.