Page 61 - Fiber Bragg Gratings

Hot hydrogenated Same as above Very good, Sn ~ 1 Can be made High stress, difficult
B-Ge codoped fiber X 10~ 3 compatible with to fabricate as
standard B-Ge fiber. Loss at
telecommunication 1500 nm
fiber
High pressure cold Easy fabrication Excellent Extremely versatile OH loss with
hydrogen soaked since all types photosensitivity, increase in index
2
germania-doped of above fiber Sn ~ I X 10~ in change. The loss
fiber may be used, standard tele- can be —0.1 dB
including communications per grating,
standard tele- fiber Limited shelf life
communication unless stored at
fiber. But low temperatures
requires high to prevent out-
pressure (up to diffusion of H 2
SOOBar) facility
High pressure cold Same as above Same as above No increase in loss Extremely expensive
deuterium soaked at 1300/1500 nm option. Also
germania-doped since OD(OH) limited shelf life
fiber overtones are not unless stored at
in second or third low temperatures
telecommunica- to prevent out-
tions window diffusion of D 2
High-pressure Same as above Can photosensitize Intracore cavity Requires 193-nm
hydrogen soaking many types of fiber gratings radiation for
of phosphorus rare- doped silica possible for fiber useful index
earth-doped fiber fibers lasers — no splice changes and ease
(Ge free) loss. of writing