Investigation of H/sub 2/ in- and out-diffusion impact on long-period grating devices

Summary form only given. H/sub 2/-loading is an established technique to photosensitise fibres for fabricating short-period (fibre Bragg gratings FBGs) and long-period gratings (LPGs). However, the H/sub 2/-diffusion effect on the spectral response is far more significant in LPGs than in FBGs (reported previously). For a systematical investigation we have assessed this effect in LPGs for H/sub 2/ in- and out-diffusion at high- and low-pressures with long and short photosensitising time lengths.