Abstract

We investigated the laser-energy-density dependence of absorption changes and paramagnetic centers induced by a cw Ar+ laser operating at 5.1 eV, in both unloaded and H2-loaded singlemode Ge-doped optical fibers. The induced absorption is measured in the blue and near ultraviolet spectral range by using the 3.1 eV photoluminescence, ascribed to Ge lone pair center (GLPC), as an in situ probe source. We find that the Ge(1) center (GeO4) is induced upon UV exposure by electron trapping on GeO4 precursors, where the free electrons are most likely produced by ionization of GLPC. Ge(1) is responsible of optical transmission loss of the fiber in the investigated range. Hydrogen loading strongly influences the generation efficiency of the several observed paramagnetic defects, leading in particular to passivation of radiation-induced Ge(2) centers.

© 2006 Optical Society of America

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    [CrossRef]
  2. A. J. Ikushima, T. Fujiwara, and K. Saito, "Silica glass: A material for photonics," J. Appl. Phys. 88, 1201-1213 (2000).
    [CrossRef]
  3. P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
    [CrossRef]
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    [CrossRef]
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    [CrossRef] [PubMed]
  7. M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
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  8. M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
    [CrossRef]
  9. M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
    [CrossRef]
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    [CrossRef]
  11. H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
    [CrossRef]
  12. M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
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  14. B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
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  15. G. Pacchioni and C. Mazzeo, "Paramagnetic centers in Ge-doped silica: A first-principles study," Phys. Rev. B. 62, 5452-5460 (2000).
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  18. T. Uchino, M. Takahashi, and T. Yoko, "Microscopic model of photoinduced and pressure-induced UV spectral changes in germanosilicate glass," Phys. Rev. B. 65, 172202-172206 (2002).
    [CrossRef]
  19. T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
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  21. L. Paccou, M. Lancry, and M. Douay, "Kinetics of UV-induced blue luminescence linked with the observation of the local mean index in fiber Bragg gratings," Opt. Express 13, 7342-7349 (2005).
    [CrossRef] [PubMed]
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    [CrossRef]
  23. R.A. Weeks, "Paramagnetic resonance of lattice defects in irradiated quartz," J. Appl. Phys. 27, 1376-1381 (1956).
    [CrossRef]
  24. S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
    [CrossRef]
  25. E.J. Friebele, D.L. Griscom, and G.H. Siegel, "Defect centers in a germanium-doped silica-core optical fiber," J. Appl. Phys. 45, 3424-3428 (1974).
    [CrossRef]
  26. T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
    [CrossRef]
  27. E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).
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    [CrossRef]
  33. K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
    [CrossRef]
  34. S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
    [CrossRef]
  35. F. Messina and M. Cannas, "Hydrogen-related conversions of Ge-related point defects in silica triggered by ultraviolet laser irradiation," Phys. Rev. B. 72, 195212 (2005).
    [CrossRef]
  36. K. Médjahdi, A. Boukenter and Y. Ouerdane,"Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers," J. Chem. Phys. 123, 214701-214704 (2005).
    [CrossRef] [PubMed]
  37. K. Awazu, H. Onuki, and K. Muta, "Mechanisms of photo-bleaching of 5 eV optical absorption band in hydrogen loaded Ge-doped SiO2," J. Non-Cryst. Solids 211, 158-163 (1997).
    [CrossRef]
  38. F. Messina and M. Cannas, "In situ observation of the generation and annealing kinetics of E’centres induced in amorphous SiO2 by 4.7eV laser irradiation," J.Phys.: Condens. Matter 17, 3837-3842 (2005).
    [CrossRef]

2005 (6)

M. Svalgaard, A. Harpøth, and T. Rosbirk, "Characterization of UV written waveguides with luminescence microscopy," Opt. Express 13, 5170-5178 (2005).
[CrossRef] [PubMed]

L. Paccou, M. Lancry, and M. Douay, "Kinetics of UV-induced blue luminescence linked with the observation of the local mean index in fiber Bragg gratings," Opt. Express 13, 7342-7349 (2005).
[CrossRef] [PubMed]

K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
[CrossRef]

F. Messina and M. Cannas, "Hydrogen-related conversions of Ge-related point defects in silica triggered by ultraviolet laser irradiation," Phys. Rev. B. 72, 195212 (2005).
[CrossRef]

K. Médjahdi, A. Boukenter and Y. Ouerdane,"Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers," J. Chem. Phys. 123, 214701-214704 (2005).
[CrossRef] [PubMed]

F. Messina and M. Cannas, "In situ observation of the generation and annealing kinetics of E’centres induced in amorphous SiO2 by 4.7eV laser irradiation," J.Phys.: Condens. Matter 17, 3837-3842 (2005).
[CrossRef]

2004 (1)

T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
[CrossRef]

2003 (4)

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

A. Sakoh, M. Takahashi, T. Yoko, J. Nishii, H. Nishiyama, and I. Miyamoto, "Photochemical process of divalent germanium responsible for photorefractive index change in GeO2-SiO2 glasses," Opt. Express 11, 2679-2688 (2003).
[CrossRef] [PubMed]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

2002 (3)

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

M. Yamaguchi, K. Saito, and A. J. Ikushima, "Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass," Phys. Rev. B 66, 132106-132110 (2002).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Microscopic model of photoinduced and pressure-induced UV spectral changes in germanosilicate glass," Phys. Rev. B. 65, 172202-172206 (2002).
[CrossRef]

2001 (2)

M. Kristensen, "Ultraviolet-light-induced processes in germanium-doped silica," Phys. Rev. B 64, 144201-144213 (2001).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
[CrossRef]

2000 (3)

G. Pacchioni and C. Mazzeo, "Paramagnetic centers in Ge-doped silica: A first-principles study," Phys. Rev. B. 62, 5452-5460 (2000).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Structure and formation mechanism of Ge E’ center from divalent defects in Ge-doped SiO2 glass," Phys. Rev. Lett. 84, 1475-1478 (2000).
[CrossRef] [PubMed]

A. J. Ikushima, T. Fujiwara, and K. Saito, "Silica glass: A material for photonics," J. Appl. Phys. 88, 1201-1213 (2000).
[CrossRef]

1999 (3)

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
[CrossRef]

1998 (1)

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

1997 (1)

K. Awazu, H. Onuki, and K. Muta, "Mechanisms of photo-bleaching of 5 eV optical absorption band in hydrogen loaded Ge-doped SiO2," J. Non-Cryst. Solids 211, 158-163 (1997).
[CrossRef]

1996 (1)

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

1995 (1)

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

1994 (1)

V.B. Neustruev, "Colour centres in germanosilicate glass and optical fibres," J. Phys.: Condens. Matter 6, 6901-6936 (1994).
[CrossRef]

1993 (1)

P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
[CrossRef]

1992 (2)

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

L. Skuja, "Isoelectronic series of twofold coordinated Si, Ge, and Sn atoms in glassy SiO2: a luminescence study," J. Non-Cryst. Solids 149, 77-95 (1992).
[CrossRef]

1991 (1)

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

1987 (1)

T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
[CrossRef]

1978 (2)

J. Vitko, "ESR studies of hydrogen hyperfine spectra in irradiated vitreous silica," J. Appl. Phys. 49, 5530-5535 (1978).
[CrossRef]

K.O. Hill, Y. Fujii, D.C. Johnson, and B.S. Kawasaki, "Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication," Appl. Phys. Lett. 32, 647-649 (1978).
[CrossRef]

1974 (1)

E.J. Friebele, D.L. Griscom, and G.H. Siegel, "Defect centers in a germanium-doped silica-core optical fiber," J. Appl. Phys. 45, 3424-3428 (1974).
[CrossRef]

1956 (1)

R.A. Weeks, "Paramagnetic resonance of lattice defects in irradiated quartz," J. Appl. Phys. 27, 1376-1381 (1956).
[CrossRef]

Abe, Y.

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

Agnello, S.

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
[CrossRef]

Anoikin, E.V.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Atkins, R.M.

P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
[CrossRef]

Awazu, K.

K. Awazu, H. Onuki, and K. Muta, "Mechanisms of photo-bleaching of 5 eV optical absorption band in hydrogen loaded Ge-doped SiO2," J. Non-Cryst. Solids 211, 158-163 (1997).
[CrossRef]

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

Boscaino, R.

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
[CrossRef]

Boukenter, A.

K. Médjahdi, A. Boukenter and Y. Ouerdane,"Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers," J. Chem. Phys. 123, 214701-214704 (2005).
[CrossRef] [PubMed]

K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
[CrossRef]

Cannas, M.

F. Messina and M. Cannas, "Hydrogen-related conversions of Ge-related point defects in silica triggered by ultraviolet laser irradiation," Phys. Rev. B. 72, 195212 (2005).
[CrossRef]

F. Messina and M. Cannas, "In situ observation of the generation and annealing kinetics of E’centres induced in amorphous SiO2 by 4.7eV laser irradiation," J.Phys.: Condens. Matter 17, 3837-3842 (2005).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
[CrossRef]

Cannizzo, A.

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

Dianov, E.M.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Douay, M.

L. Paccou, M. Lancry, and M. Douay, "Kinetics of UV-induced blue luminescence linked with the observation of the local mean index in fiber Bragg gratings," Opt. Express 13, 7342-7349 (2005).
[CrossRef] [PubMed]

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

Fleming, J.W.

T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
[CrossRef]

Friebele, E.J.

T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
[CrossRef]

E.J. Friebele, D.L. Griscom, and G.H. Siegel, "Defect centers in a germanium-doped silica-core optical fiber," J. Appl. Phys. 45, 3424-3428 (1974).
[CrossRef]

Fujii, Y.

K.O. Hill, Y. Fujii, D.C. Johnson, and B.S. Kawasaki, "Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication," Appl. Phys. Lett. 32, 647-649 (1978).
[CrossRef]

Fujimaki, M.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

Fujiwara, T.

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

A. J. Ikushima, T. Fujiwara, and K. Saito, "Silica glass: A material for photonics," J. Appl. Phys. 88, 1201-1213 (2000).
[CrossRef]

Fukumi, N.

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

Garapon, J.

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

Gelardi, F.M.

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
[CrossRef]

Goutaland, F.

K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
[CrossRef]

Grandi, S.

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

Griscom, D.L.

T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
[CrossRef]

E.J. Friebele, D.L. Griscom, and G.H. Siegel, "Defect centers in a germanium-doped silica-core optical fiber," J. Appl. Phys. 45, 3424-3428 (1974).
[CrossRef]

Guryanov, A.N.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Gusovsky, D.D.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Harpøth, A.

Hill, K.O.

K.O. Hill, Y. Fujii, D.C. Johnson, and B.S. Kawasaki, "Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication," Appl. Phys. Lett. 32, 647-649 (1978).
[CrossRef]

Hosono, H.

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

Ichii, K.

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

Ikushima, A. J.

M. Yamaguchi, K. Saito, and A. J. Ikushima, "Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass," Phys. Rev. B 66, 132106-132110 (2002).
[CrossRef]

A. J. Ikushima, T. Fujiwara, and K. Saito, "Silica glass: A material for photonics," J. Appl. Phys. 88, 1201-1213 (2000).
[CrossRef]

Johnson, D.C.

K.O. Hill, Y. Fujii, D.C. Johnson, and B.S. Kawasaki, "Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication," Appl. Phys. Lett. 32, 647-649 (1978).
[CrossRef]

Kasahara, T.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

Kato, M.

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

Katoh, T.

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

Kawamoto, Y.

H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
[CrossRef]

Kawamura, K.

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

Kawasaki, B.S.

K.O. Hill, Y. Fujii, D.C. Johnson, and B.S. Kawasaki, "Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication," Appl. Phys. Lett. 32, 647-649 (1978).
[CrossRef]

Kawazoe, H.

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

Kawazoe, K.M.H.

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

Kinser, D.L.

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

Kintaka, K.

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

Kohyama, M.

T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
[CrossRef]

Kristensen, M.

M. Kristensen, "Ultraviolet-light-induced processes in germanium-doped silica," Phys. Rev. B 64, 144201-144213 (2001).
[CrossRef]

Krupa, J.C.

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

La Mattina, F.

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

Lancry, M.

Lemaire, P.J.

P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
[CrossRef]

Leone, M.

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

Lu, G. -H.

T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
[CrossRef]

M´edjahdi, K.

K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
[CrossRef]

K. Médjahdi, A. Boukenter and Y. Ouerdane,"Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers," J. Chem. Phys. 123, 214701-214704 (2005).
[CrossRef] [PubMed]

Magistri, A.

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

Mashinsky, V.M.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Mazzeo, C.

G. Pacchioni and C. Mazzeo, "Paramagnetic centers in Ge-doped silica: A first-principles study," Phys. Rev. B. 62, 5452-5460 (2000).
[CrossRef]

Messina, F.

F. Messina and M. Cannas, "In situ observation of the generation and annealing kinetics of E’centres induced in amorphous SiO2 by 4.7eV laser irradiation," J.Phys.: Condens. Matter 17, 3837-3842 (2005).
[CrossRef]

F. Messina and M. Cannas, "Hydrogen-related conversions of Ge-related point defects in silica triggered by ultraviolet laser irradiation," Phys. Rev. B. 72, 195212 (2005).
[CrossRef]

Mirosh-nichenko, S.I.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Miyamoto, I.

Miyazaki, N.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

Mizrahi, V.

P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
[CrossRef]

Muta, K.

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

K. Awazu, H. Onuki, and K. Muta, "Mechanisms of photo-bleaching of 5 eV optical absorption band in hydrogen loaded Ge-doped SiO2," J. Non-Cryst. Solids 211, 158-163 (1997).
[CrossRef]

Neustruev, V.B.

V.B. Neustruev, "Colour centres in germanosilicate glass and optical fibres," J. Phys.: Condens. Matter 6, 6901-6936 (1994).
[CrossRef]

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Niay, P.

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

Nishi, J.

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

Nishii, J.

A. Sakoh, M. Takahashi, T. Yoko, J. Nishii, H. Nishiyama, and I. Miyamoto, "Photochemical process of divalent germanium responsible for photorefractive index change in GeO2-SiO2 glasses," Opt. Express 11, 2679-2688 (2003).
[CrossRef] [PubMed]

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
[CrossRef]

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

Nishikawa, H.

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

Nishiyama, H.

Ohki, Y.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

Onuki, H.

K. Awazu, H. Onuki, and K. Muta, "Mechanisms of photo-bleaching of 5 eV optical absorption band in hydrogen loaded Ge-doped SiO2," J. Non-Cryst. Solids 211, 158-163 (1997).
[CrossRef]

Ouerdane, Y.

K. Médjahdi, A. Boukenter and Y. Ouerdane,"Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers," J. Chem. Phys. 123, 214701-214704 (2005).
[CrossRef] [PubMed]

K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
[CrossRef]

Pacchioni, G.

G. Pacchioni and C. Mazzeo, "Paramagnetic centers in Ge-doped silica: A first-principles study," Phys. Rev. B. 62, 5452-5460 (2000).
[CrossRef]

Paccou, L.

Poumellec, B.

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

Reed, W.A.

P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
[CrossRef]

Rosbirk, T.

Saito, K.

M. Yamaguchi, K. Saito, and A. J. Ikushima, "Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass," Phys. Rev. B 66, 132106-132110 (2002).
[CrossRef]

A. J. Ikushima, T. Fujiwara, and K. Saito, "Silica glass: A material for photonics," J. Appl. Phys. 88, 1201-1213 (2000).
[CrossRef]

Sakoh, A.

Seol, K.S.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

Shigemura, H.

H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
[CrossRef]

Shimoto, S.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

Siegel, G.H.

E.J. Friebele, D.L. Griscom, and G.H. Siegel, "Defect centers in a germanium-doped silica-core optical fiber," J. Appl. Phys. 45, 3424-3428 (1974).
[CrossRef]

Skuja, L.

L. Skuja, "Isoelectronic series of twofold coordinated Si, Ge, and Sn atoms in glassy SiO2: a luminescence study," J. Non-Cryst. Solids 149, 77-95 (1992).
[CrossRef]

Svalgaard, M.

Takahashi, M.

A. Sakoh, M. Takahashi, T. Yoko, J. Nishii, H. Nishiyama, and I. Miyamoto, "Photochemical process of divalent germanium responsible for photorefractive index change in GeO2-SiO2 glasses," Opt. Express 11, 2679-2688 (2003).
[CrossRef] [PubMed]

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Microscopic model of photoinduced and pressure-induced UV spectral changes in germanosilicate glass," Phys. Rev. B. 65, 172202-172206 (2002).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Structure and formation mechanism of Ge E’ center from divalent defects in Ge-doped SiO2 glass," Phys. Rev. Lett. 84, 1475-1478 (2000).
[CrossRef] [PubMed]

H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
[CrossRef]

Tamura, T.

T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
[CrossRef]

Tikhomirov, V.A.

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Tokuda, Y.

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

Tokuhiro, S.

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

Tsai, T.E.

T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
[CrossRef]

Uchino, T.

T. Uchino, M. Takahashi, and T. Yoko, "Microscopic model of photoinduced and pressure-induced UV spectral changes in germanosilicate glass," Phys. Rev. B. 65, 172202-172206 (2002).
[CrossRef]

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Structure and formation mechanism of Ge E’ center from divalent defects in Ge-doped SiO2 glass," Phys. Rev. Lett. 84, 1475-1478 (2000).
[CrossRef] [PubMed]

Vitko, J.

J. Vitko, "ESR studies of hydrogen hyperfine spectra in irradiated vitreous silica," J. Appl. Phys. 49, 5530-5535 (1978).
[CrossRef]

Watanabe, T.

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

Weeks, R.A.

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

R.A. Weeks, "Paramagnetic resonance of lattice defects in irradiated quartz," J. Appl. Phys. 27, 1376-1381 (1956).
[CrossRef]

Yagi, K.

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

Yamaguchi, M.

M. Yamaguchi, K. Saito, and A. J. Ikushima, "Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass," Phys. Rev. B 66, 132106-132110 (2002).
[CrossRef]

Yamamoto, R.

T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
[CrossRef]

Yamanaka, H.

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

Yoko, T.

A. Sakoh, M. Takahashi, T. Yoko, J. Nishii, H. Nishiyama, and I. Miyamoto, "Photochemical process of divalent germanium responsible for photorefractive index change in GeO2-SiO2 glasses," Opt. Express 11, 2679-2688 (2003).
[CrossRef] [PubMed]

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Microscopic model of photoinduced and pressure-induced UV spectral changes in germanosilicate glass," Phys. Rev. B. 65, 172202-172206 (2002).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Structure and formation mechanism of Ge E’ center from divalent defects in Ge-doped SiO2 glass," Phys. Rev. Lett. 84, 1475-1478 (2000).
[CrossRef] [PubMed]

Appl. Phys. Lett. (1)

K.O. Hill, Y. Fujii, D.C. Johnson, and B.S. Kawasaki, "Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication," Appl. Phys. Lett. 32, 647-649 (1978).
[CrossRef]

Electron. Lett. (1)

P.J. Lemaire, R.M. Atkins, V. Mizrahi, and W.A. Reed, "High pressure H2 loading as a technique for achieving ultrahigh UV photosensitivity and thermal sensitivity in GeO2 doped optical fibres," Electron. Lett. 29, 1191-1193 (1993).
[CrossRef]

J. Appl. Phys. (7)

A. J. Ikushima, T. Fujiwara, and K. Saito, "Silica glass: A material for photonics," J. Appl. Phys. 88, 1201-1213 (2000).
[CrossRef]

H. Shigemura, Y. Kawamoto, J. Nishii, and M. Takahashi, "Ultraviolet-photosensitive effect of sol-gel-derived GeO2-SiO2 glasses, " J. Appl. Phys. 85, 3413-3418 (1999).
[CrossRef]

M. Takahashi, K. Ichii, Y. Tokuda, T. Uchino, T. Yoko, J. Nishii, and T. Fujiwara, "Photochemical reaction of divalent-germanium center in germanosilicate glasses under intense near-ultraviolet laser excitation: Origin of 5.7 eV band and site selective excitation of divalent-germanium center," J. Appl. Phys. 92, 3442-3446 (2002).
[CrossRef]

R.A. Weeks, "Paramagnetic resonance of lattice defects in irradiated quartz," J. Appl. Phys. 27, 1376-1381 (1956).
[CrossRef]

E.J. Friebele, D.L. Griscom, and G.H. Siegel, "Defect centers in a germanium-doped silica-core optical fiber," J. Appl. Phys. 45, 3424-3428 (1974).
[CrossRef]

T.E. Tsai, D.L. Griscom, E.J. Friebele, and J.W. Fleming, "Radiation induced defect centers in high purity GeO2 glass," J. Appl. Phys. 62, 2264-2268 (1987).
[CrossRef]

J. Vitko, "ESR studies of hydrogen hyperfine spectra in irradiated vitreous silica," J. Appl. Phys. 49, 5530-5535 (1978).
[CrossRef]

J. Chem. Phys. (1)

K. Médjahdi, A. Boukenter and Y. Ouerdane,"Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers," J. Chem. Phys. 123, 214701-214704 (2005).
[CrossRef] [PubMed]

J. Non Cryst. Solids (2)

S. Agnello, R. Boscaino, M. Cannas, F.M. Gelardi, F. La Mattina, S. Grandi, and A. Magistri, "Ge related centers induced by gamma irradiation in sol˝Ugel Ge-doped silica," J. Non Cryst. Solids 322, 134-138 (2003).
[CrossRef]

B. Poumellec, M. Douay, J.C. Krupa, J. Garapon, and P. Niay, "Comparison of UV optical absorption and UV excited luminescence behaviours in Ge doped silica under H2 loading or CW UV laser irradiation," J. Non Cryst. Solids 317, 319-334 (2003).
[CrossRef]

J. Non-Cryst. Solids (3)

K. Awazu, H. Onuki, and K. Muta, "Mechanisms of photo-bleaching of 5 eV optical absorption band in hydrogen loaded Ge-doped SiO2," J. Non-Cryst. Solids 211, 158-163 (1997).
[CrossRef]

K. Médjahdi, F. Goutaland, A. Boukenter, and Y. Ouerdane, "Ultraviolet-induced absorption during very short continuous exposure in Ge-doped optical fiber, " J. Non-Cryst. Solids 351, 1835-1839 (2005).
[CrossRef]

L. Skuja, "Isoelectronic series of twofold coordinated Si, Ge, and Sn atoms in glassy SiO2: a luminescence study," J. Non-Cryst. Solids 149, 77-95 (1992).
[CrossRef]

J. Phys.: Condens. Matter (1)

V.B. Neustruev, "Colour centres in germanosilicate glass and optical fibres," J. Phys.: Condens. Matter 6, 6901-6936 (1994).
[CrossRef]

J.Phys.: Condens. Matter (1)

F. Messina and M. Cannas, "In situ observation of the generation and annealing kinetics of E’centres induced in amorphous SiO2 by 4.7eV laser irradiation," J.Phys.: Condens. Matter 17, 3837-3842 (2005).
[CrossRef]

Opt. Express (3)

Phys. Rev B (1)

T. Tamura, G. -H. Lu, M. Kohyama, and R. Yamamoto, "E’ center in Ge-doped SiO2 glass,"Phys. Rev B 70, 153201-153205 (2004).
[CrossRef]

Phys. Rev. B (9)

S. Agnello, R. Boscaino, M. Cannas, and F.M. Gelardi, "Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation,"Phys. Rev. B 64, 174423-174428 (2001).
[CrossRef]

M. Fujimaki,K. Yagi, Y. Ohki, H. Nishikawa, and K. Awazu, "Laser-power dependence of absorption changes in Ge-doped SiO2 glass induced by a KrF excimer laser,"Phys. Rev. B 53, 9859-9862 (1996).
[CrossRef]

M. Fujimaki, T. Watanabe, T. Katoh, T. Kasahara, N. Miyazaki, Y. Ohki, and H. Nishikawa, "Structures and generation mechanisms of paramagnetic centers and absorption bands responsible for Ge-doped SiO2 optical-fiber gratings," Phys. Rev. B 57, 3920-3926 (1998).
[CrossRef]

M. Fujimaki, T. Kasahara, S. Shimoto, N. Miyazaki, S. Tokuhiro, K.S. Seol, and Y. Ohki, "Structural changes induced by KrF excimer laser photons in H2-loaded Ge-doped SiO2 glass," Phys. Rev. B 60, 4682-4687 (1999).
[CrossRef]

J. Nishi, K. Kintaka, H. Hosono, H. Kawazoe, M. Kato, and K. Muta, "Pair generation of Ge electron centers and self-trapped hole centers in GeO2-SiO2 glasses by KrF excimer-laser irradiation," Phys. Rev. B 60, 7166-7169 (1999).
[CrossRef]

H. Hosono, Y. Abe, D.L. Kinser, R.A. Weeks, and K.M.H. Kawazoe, "Nature and origin of the 5-eV band in SiO2:GeO2 glasses," Phys. Rev. B 46, 11445-11451 (1992).
[CrossRef]

J. Nishii, N. Fukumi, H. Yamanaka, K. Kawamura, H. Hosono, and H. Kawazoe, "Photochemical reactions in GeO2-SiO2 glasses induced by ultraviolet irradiation: Comparison between Hg lamp and excimer laser," Phys. Rev. B 52, 1661-1665 (1995).
[CrossRef]

M. Kristensen, "Ultraviolet-light-induced processes in germanium-doped silica," Phys. Rev. B 64, 144201-144213 (2001).
[CrossRef]

M. Yamaguchi, K. Saito, and A. J. Ikushima, "Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass," Phys. Rev. B 66, 132106-132110 (2002).
[CrossRef]

Phys. Rev. B. (4)

G. Pacchioni and C. Mazzeo, "Paramagnetic centers in Ge-doped silica: A first-principles study," Phys. Rev. B. 62, 5452-5460 (2000).
[CrossRef]

T. Uchino, M. Takahashi, and T. Yoko, "Microscopic model of photoinduced and pressure-induced UV spectral changes in germanosilicate glass," Phys. Rev. B. 65, 172202-172206 (2002).
[CrossRef]

S. Agnello, R. Boscaino, M. Cannas, A. Cannizzo, F.M. Gelardi, S. Grandi, and M. Leone, "Temperature and excitation energy dependence of decay processes of luminescence in Ge-doped silica," Phys. Rev. B. 68, 165201 (2003).
[CrossRef]

F. Messina and M. Cannas, "Hydrogen-related conversions of Ge-related point defects in silica triggered by ultraviolet laser irradiation," Phys. Rev. B. 72, 195212 (2005).
[CrossRef]

Phys. Rev. Lett. (1)

T. Uchino, M. Takahashi, and T. Yoko, "Structure and formation mechanism of Ge E’ center from divalent defects in Ge-doped SiO2 glass," Phys. Rev. Lett. 84, 1475-1478 (2000).
[CrossRef] [PubMed]

Sov. Lightwave Commun. (1)

E.V. Anoikin, A.N. Guryanov, D.D. Gusovsky, E.M. Dianov, V.M. Mashinsky, S.I. Mirosh-nichenko, V.B. Neustruev, and V.A. Tikhomirov, "Photoinduced defects in silica glass doped with germanium and cerium," Sov. Lightwave Commun. 1, 129-36 (1991).

Other (2)

C.P. Slichter, "Principles of Magnetic Resonance," ISBN 962-430-004-6 Springer-Verlag Hong Kong (1991).

A. Abragam, B. Bleaney, "Electronic paramagnetic resonance of transition ions," ISBN 0198512503 Clarendon Press, Oxford (1970).

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Figures (6)

Fig. 1.
Fig. 1.

Experimental set-up used to measure in situ the photoinduced absorption in a singlemode fiber.

Fig. 2.
Fig. 2.

(a) Evolution of laser-excited PL spectra peaked around 3.1 eV transmitted within the irradiated part of the unloaded fiber during the irradiation. The inset depicts the evolution of the PL intensity, for a given energy, as a function of the irradiated length. (b) OA spectra induced after various energy densities.

Fig. 3.
Fig. 3.

Absorption coefficient at 3.1 eV (Δα 3.1) as a function of energy density in both unloaded and H2-loaded fibers.

Fig. 4.
Fig. 4.

ESR spectra detected in unloaded (a) and H2-loaded (b) fibers after irradiation at 0.8 J/cm2. Black solid lines plot the best fitting functions obtained as a linear combinations of the three base lineshapes reported in panel (c) (see text). The inset reports the ESR doublet of H(II) centers detected in H2-loaded fibers.

Fig. 5.
Fig. 5.

Concentration of paramagnetic centers as a function of energy density detected in the two kinds of fibers.

Fig. 6.
Fig. 6.

(a) Correlation between concentrations of laser-induced Ge(1) centers and absorption coefficients at 3.1 eV (Δα 3.1) measured after each sequence of irradiation. The data are taken from Figs. 3 and 5. (b) Correlation between the Ge(1) and Ge(2) centers concentrations. The open and the closed circles are for unloaded and H2-loaded fibers, respectively. Solid lines are obtained by a least square fit to the data.

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

X + Ge O 4 + h ν Ge ( 2 ) or Ge ( 1 )
GLPC + Ge O 4 + h ν Ge ( 2 ) + e + Ge O 4 Ge ( 1 ) + Ge ( 2 )
Ge ( 2 ) + H 2 ( GLPC H ) +

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