Formation of thermally stable chemical composition gratings in optical fibers

Experimental results and a discussion of possible chemical pathways in the formation of thermally stable chemical composition gratings in optical fibers are presented. Gratings are formed through high-temperature treatment of UV-exposed hydrogen-loaded fibers. The final refractive-index modulation is ascribed to variations in fluorine concentration attained by periodically increased diffusion of fluorine. The mechanism behind this increase is the formation of mobile hydrogen fluoride from chemical reactions of fluorine and UV-induced hydroxyl, which occur with the spatial periodicity of the UV pattern. A hydroxyl-assisted increase in fluorine diffusion has been verified by time-of-flight secondary-ion mass spectroscopy. Formation of ultrastable grating by periodic variation of oxygen concentration through diffusion of molecular water is also discussed.

[1]  Gerald Meltz,et al.  Bragg grating formation and germanosilicate fiber photosensitivity , 1991, Other Conferences.

[2]  W. F. Liu,et al.  Thermal decay of fiber Bragg gratings of positive and negative index changes formed at 193 nm in a boron-codoped germanosilicate fiber. , 1997, Applied optics.

[3]  P. Lemaire,et al.  High pressure H/sub 2/ loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO/sub 2/ doped optical fibres , 1993 .

[4]  Victor Mizrahi,et al.  248 nm induced vacuum UV spectral changes in optical fibre preform cores: support for a colour centre model of photosensitivity , 1993 .

[5]  Utlra-Thermostable Long-Period Gratings Written in Nitrogen-Doped Silica Fibers , 1998 .

[6]  High temperature miniature oven with low thermal gradient for processing fiber Bragg gratings , 2001 .

[7]  Bragg gratings in ternary SiO(2):SnO(2):Na(2)O optical glass fibers. , 2000, Optics letters.

[8]  Johannes Kirchhof,et al.  Diffusion behaviour of fluorine in silica glass , 1995 .

[9]  R P Salathé,et al.  Tension increase correlated to refractive-index change in fibers containing UV-written Bragg gratings. , 1995, Optics letters.

[10]  P. Russell,et al.  100% reflectivity Bragg reflectors produced in optical fibres by single excimer laser pulses , 1993 .

[11]  J. Stone,et al.  Interactions of hydrogen and deuterium with silica optical fibers: A review , 1987 .

[12]  S B Poole,et al.  Stress-birefringence reduction in elliptical-core fibers under ultraviolet irradiation. , 1992, Optics letters.

[13]  S. Unger,et al.  Hydrogen-induced hydroxyl profiles in doped silica layers , 1995 .

[14]  Don Monroe,et al.  DECAY OF ULTRAVIOLET-INDUCED FIBER BRAGG GRATINGS , 1994 .

[15]  D. Hand,et al.  Photoinduced refractive-index changes in germanosilicate fibers. , 1990, Optics letters.

[16]  M. Fokine,et al.  Large increase in photosensitivity through massive hydroxyl formation. , 2000, Optics letters.

[17]  John E. Sipe,et al.  Long-period fiber gratings as band-rejection filters , 1995 .

[18]  Growth kinetics and thermal annealing of UV-induced H-bearing species in hydrogen loaded germanosilicate fibre preforms , 1999 .

[19]  R. R. Khrapko,et al.  Grating formation in a germanium free silicon oxynitride fibre , 1997 .

[20]  M Aslund,et al.  Annealing properties of gratings written into UV-presensitized hydrogen-outdiffused optical fiber. , 2000, Optics letters.