Page 52 - Fiber Bragg Gratings
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2A. Photosensitization techniques 33
Figure 2.10: In-diffusion profile of hydrogen at 200 bar pressure in a 125-
/jocn. diameter fiber as a function of time at 23°C (courtesy F. Bhakti, Ref. [73]).
Figure 2.11: Out-diffusion profile of hydrogen in a 125-/u,m diameter fiber
at 23°C (courtesy F. Bhakti, Ref. [73]).
to verify the concentration of hydrogen in the core [74,75]; the absorption
4
at 1.245 /urn is ~3 dB/(mol% H 2) (equivalent to 10 ppm in a mole of
silica).
The wavelength shifts of long-period gratings (LPGs, see Chapter 4)
resonances can be in excess of 150 nm to the long wavelength as the
