Abstract

We compare the results of thermally induced isochronal and isothermal decays of fiber Bragg gratings written through cw exposure of an unloaded germanosilicate fiber. We show that isochronal step decays can be used to predict isothermal decays, provided that some corrections are carried out to take into account a reversible change in grating reflectivity induced by the increase of the fiber temperature. The isochronal accelerated-aging method enables one to sample most of the initial distribution of trapped site energies in a fairly short time. Taking advantage of this property of the method, we show that the initial distribution for a weak grating is similar to those for stronger gratings. The consequences of this observation are discussed within the framework of the various reaction pathway model.

© 2000 Optical Society of America

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References

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  1. T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
    [CrossRef]
  2. H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
    [CrossRef]
  3. D. L. Williams, R. P. Smith, “Accelerated lifetime tests on UV written intra-core gratings in boron germania codoped silica fibre,” Electron. Lett. 31, 2120–2121 (1995).
    [CrossRef]
  4. R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.
  5. S. Kannan, J. S. Y. Guo, P. J. Lemaire, “Thermal reliability of strong Bragg gratings written in hydrogen sensitized fibers,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 84–85.
  6. I. Riant, S. Borne, P. Sansonetti, “Dependence of fiber Bragg grating thermal stability on grating fabrication process,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 86–87.
  7. S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
    [CrossRef]
  8. S. Kannan, J. Z. Y. Guo, P. J. Lemaire, “Thermal stability analysis of UV-induced fiber Bragg gratings,” J. Lightwave Technol. 15, 1478–1483 (1997).
    [CrossRef]
  9. S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.
  10. G. Robert, I. Riant, “Demonstration of two distributions of defect centers in hydrogen-loaded high germanium content fibers,” in Optical Fiber Communication Conference, Vol. 6 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 180–181.
  11. B. Poumellec, “Links between writing and erasing (or stability) of Bragg gratings in disordered media,” in Bragg Gratings Photosensitivity and Poling in Glass Fibers and Waveguides: Applications and Fundamentals, Vol. 17 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 178–180.
  12. I. Riant, B. Poumellec, “Thermal decay of gratings written in hydrogen-loaded germanosilicate fibres,” Electron. Lett. 34, 1603–1604 (1998).
    [CrossRef]
  13. B. Poumellec, “Links between writing and erasure (or stability) of Bragg gratings in disordered media,” J. Non-Cryst. Solids 239, 108–115 (1998).
    [CrossRef]
  14. S. Ishikawa, A. I. Inoue, M. Harumoto, “Adequate aging condition for fiber Bragg grating based on simple power law model,” in Optical Fiber Communication Conference, Vol. 2 of 1998 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1998), pp. 183–184.
  15. W. Primak, “Large temperature range annealing,” J. Appl. Phys. 31, 1524–1533 (1960).
    [CrossRef]
  16. K. S. Chiang, M. G. Sceats, D. Wong, “Ultraviolet photolytic induces changes in optical fibers: the thermal expansion coefficient,” Opt. Lett. 18, 965–967 (1993).
    [CrossRef] [PubMed]

1998 (2)

I. Riant, B. Poumellec, “Thermal decay of gratings written in hydrogen-loaded germanosilicate fibres,” Electron. Lett. 34, 1603–1604 (1998).
[CrossRef]

B. Poumellec, “Links between writing and erasure (or stability) of Bragg gratings in disordered media,” J. Non-Cryst. Solids 239, 108–115 (1998).
[CrossRef]

1997 (2)

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
[CrossRef]

S. Kannan, J. Z. Y. Guo, P. J. Lemaire, “Thermal stability analysis of UV-induced fiber Bragg gratings,” J. Lightwave Technol. 15, 1478–1483 (1997).
[CrossRef]

1995 (2)

H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
[CrossRef]

D. L. Williams, R. P. Smith, “Accelerated lifetime tests on UV written intra-core gratings in boron germania codoped silica fibre,” Electron. Lett. 31, 2120–2121 (1995).
[CrossRef]

1994 (1)

T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
[CrossRef]

1993 (1)

1960 (1)

W. Primak, “Large temperature range annealing,” J. Appl. Phys. 31, 1524–1533 (1960).
[CrossRef]

Baker, S. R.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
[CrossRef]

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Baker, V.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
[CrossRef]

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Baulcomb, A. S.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Borne, S.

I. Riant, S. Borne, P. Sansonetti, “Dependence of fiber Bragg grating thermal stability on grating fabrication process,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 86–87.

Byron, K. C.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Chiang, K. S.

Clements, S. J.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Egan, R. J.

R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.

Erdogan, T.

T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
[CrossRef]

Fielding, A.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Gallagher, M. D.

H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
[CrossRef]

Gilbert, S. L.

H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
[CrossRef]

Goodchild, D.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
[CrossRef]

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Guo, J. S. Y.

S. Kannan, J. S. Y. Guo, P. J. Lemaire, “Thermal reliability of strong Bragg gratings written in hydrogen sensitized fibers,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 84–85.

Guo, J. Z. Y.

S. Kannan, J. Z. Y. Guo, P. J. Lemaire, “Thermal stability analysis of UV-induced fiber Bragg gratings,” J. Lightwave Technol. 15, 1478–1483 (1997).
[CrossRef]

Harumoto, M.

S. Ishikawa, A. I. Inoue, M. Harumoto, “Adequate aging condition for fiber Bragg grating based on simple power law model,” in Optical Fiber Communication Conference, Vol. 2 of 1998 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1998), pp. 183–184.

Hill, P.

R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.

Inglis, H. G.

R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.

Inoue, A. I.

S. Ishikawa, A. I. Inoue, M. Harumoto, “Adequate aging condition for fiber Bragg grating based on simple power law model,” in Optical Fiber Communication Conference, Vol. 2 of 1998 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1998), pp. 183–184.

Ishikawa, S.

S. Ishikawa, A. I. Inoue, M. Harumoto, “Adequate aging condition for fiber Bragg grating based on simple power law model,” in Optical Fiber Communication Conference, Vol. 2 of 1998 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1998), pp. 183–184.

Kannan, S.

S. Kannan, J. Z. Y. Guo, P. J. Lemaire, “Thermal stability analysis of UV-induced fiber Bragg gratings,” J. Lightwave Technol. 15, 1478–1483 (1997).
[CrossRef]

S. Kannan, J. S. Y. Guo, P. J. Lemaire, “Thermal reliability of strong Bragg gratings written in hydrogen sensitized fibers,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 84–85.

Krug, P. A.

R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.

Lemaire, P. J.

S. Kannan, J. Z. Y. Guo, P. J. Lemaire, “Thermal stability analysis of UV-induced fiber Bragg gratings,” J. Lightwave Technol. 15, 1478–1483 (1997).
[CrossRef]

T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
[CrossRef]

S. Kannan, J. S. Y. Guo, P. J. Lemaire, “Thermal reliability of strong Bragg gratings written in hydrogen sensitized fibers,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 84–85.

Lidgard, A.

H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
[CrossRef]

Mizrahi, V.

T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
[CrossRef]

Monroe, D.

T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
[CrossRef]

Ouellette, F.

R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.

Patrick, H.

H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
[CrossRef]

Poumellec, B.

B. Poumellec, “Links between writing and erasure (or stability) of Bragg gratings in disordered media,” J. Non-Cryst. Solids 239, 108–115 (1998).
[CrossRef]

I. Riant, B. Poumellec, “Thermal decay of gratings written in hydrogen-loaded germanosilicate fibres,” Electron. Lett. 34, 1603–1604 (1998).
[CrossRef]

B. Poumellec, “Links between writing and erasing (or stability) of Bragg gratings in disordered media,” in Bragg Gratings Photosensitivity and Poling in Glass Fibers and Waveguides: Applications and Fundamentals, Vol. 17 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 178–180.

Primak, W.

W. Primak, “Large temperature range annealing,” J. Appl. Phys. 31, 1524–1533 (1960).
[CrossRef]

Riant, I.

I. Riant, B. Poumellec, “Thermal decay of gratings written in hydrogen-loaded germanosilicate fibres,” Electron. Lett. 34, 1603–1604 (1998).
[CrossRef]

I. Riant, S. Borne, P. Sansonetti, “Dependence of fiber Bragg grating thermal stability on grating fabrication process,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 86–87.

G. Robert, I. Riant, “Demonstration of two distributions of defect centers in hydrogen-loaded high germanium content fibers,” in Optical Fiber Communication Conference, Vol. 6 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 180–181.

Robert, G.

G. Robert, I. Riant, “Demonstration of two distributions of defect centers in hydrogen-loaded high germanium content fibers,” in Optical Fiber Communication Conference, Vol. 6 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 180–181.

Rourke, H. N.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
[CrossRef]

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

Sansonetti, P.

I. Riant, S. Borne, P. Sansonetti, “Dependence of fiber Bragg grating thermal stability on grating fabrication process,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 86–87.

Sceats, M. G.

Smith, R. P.

D. L. Williams, R. P. Smith, “Accelerated lifetime tests on UV written intra-core gratings in boron germania codoped silica fibre,” Electron. Lett. 31, 2120–2121 (1995).
[CrossRef]

Williams, D. L.

D. L. Williams, R. P. Smith, “Accelerated lifetime tests on UV written intra-core gratings in boron germania codoped silica fibre,” Electron. Lett. 31, 2120–2121 (1995).
[CrossRef]

Wong, D.

Electron. Lett. (2)

D. L. Williams, R. P. Smith, “Accelerated lifetime tests on UV written intra-core gratings in boron germania codoped silica fibre,” Electron. Lett. 31, 2120–2121 (1995).
[CrossRef]

I. Riant, B. Poumellec, “Thermal decay of gratings written in hydrogen-loaded germanosilicate fibres,” Electron. Lett. 34, 1603–1604 (1998).
[CrossRef]

J. Appl. Phys. (3)

T. Erdogan, V. Mizrahi, P. J. Lemaire, D. Monroe, “Decay of ultraviolet-induced fiber Bragg gratings,” J. Appl. Phys. 76, 73–80 (1994).
[CrossRef]

H. Patrick, S. L. Gilbert, A. Lidgard, M. D. Gallagher, “Annealing of Bragg gratings in hydrogen-loaded optical fiber,” J. Appl. Phys. 78, 2940–2945 (1995).
[CrossRef]

W. Primak, “Large temperature range annealing,” J. Appl. Phys. 31, 1524–1533 (1960).
[CrossRef]

J. Lightwave Technol. (2)

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, “Thermal decay of fiber Bragg gratings written in boron and germanium codoped silica fiber,” J. Lightwave Technol. 15, 1470–1477 (1997).
[CrossRef]

S. Kannan, J. Z. Y. Guo, P. J. Lemaire, “Thermal stability analysis of UV-induced fiber Bragg gratings,” J. Lightwave Technol. 15, 1478–1483 (1997).
[CrossRef]

J. Non-Cryst. Solids (1)

B. Poumellec, “Links between writing and erasure (or stability) of Bragg gratings in disordered media,” J. Non-Cryst. Solids 239, 108–115 (1998).
[CrossRef]

Opt. Lett. (1)

Other (7)

S. Ishikawa, A. I. Inoue, M. Harumoto, “Adequate aging condition for fiber Bragg grating based on simple power law model,” in Optical Fiber Communication Conference, Vol. 2 of 1998 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1998), pp. 183–184.

S. R. Baker, H. N. Rourke, V. Baker, D. Goodchild, A. S. Baulcomb, K. C. Byron, A. Fielding, S. J. Clements, “Thermal decay of fibre Bragg gratings,” in 23rd European Conference on Optical Communication (Institution of Electrical Engineers, London, 1997), pp. 57–60.

G. Robert, I. Riant, “Demonstration of two distributions of defect centers in hydrogen-loaded high germanium content fibers,” in Optical Fiber Communication Conference, Vol. 6 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 180–181.

B. Poumellec, “Links between writing and erasing (or stability) of Bragg gratings in disordered media,” in Bragg Gratings Photosensitivity and Poling in Glass Fibers and Waveguides: Applications and Fundamentals, Vol. 17 of 1997 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1997), pp. 178–180.

R. J. Egan, H. G. Inglis, P. Hill, P. A. Krug, F. Ouellette, “Effects of hydrogen loading and grating strength on the thermal stability of fiber Bragg gratings,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 83–84.

S. Kannan, J. S. Y. Guo, P. J. Lemaire, “Thermal reliability of strong Bragg gratings written in hydrogen sensitized fibers,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 84–85.

I. Riant, S. Borne, P. Sansonetti, “Dependence of fiber Bragg grating thermal stability on grating fabrication process,” in Optical Fiber Communication Conference, Vol. 2 of 1996 OSA Technical Digest Series (Optical Society of America, Washington, D. C., 1996), pp. 86–87.

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Figures (11)

Fig. 1
Fig. 1

Isochronal decays of gratings written in the unloaded fiber. Three heating times (triangles, 300 s; squares, 1800 s; circles, 86,400 s) were investigated. Each experimental point corresponds to the heating of a virgin grating. The solid curves are fits to Eq. (3).

Fig. 2
Fig. 2

Isochronal step annealing of four grating (open symbols) heating times (60, 300, 1800, and 86,400 s). The filled symbols correspond to data from Fig. 1. The solid curves are fits to Eq. (3).

Fig. 3
Fig. 3

Normalized integrated coupling constant as a function of demarcation energy (E d = k B T ln(k 0 t). The thermal history of each grating was taken into account. The solid curve is a fit of the data to a third-order polynomial equation.

Fig. 4
Fig. 4

Correction of the demarcation energy introduced at the last step of the iterative process when the grating’s thermal history is taken into account. Open circles, 60 s; filled circle, 300 s; open diamonds, 1800 s; filled diamonds, 86,400 s.

Fig. 5
Fig. 5

Comparison of experimental and calculated isothermal decays of gratings at 423, 523, and 623 K. Filled symbols, experimental data; dotted curves, data calculated from the fit of the aging curve in Fig. 3.

Fig. 6
Fig. 6

Transmission spectrum of a preannealed grating, showing temperatures at which portions of the spectrum were recorded.

Fig. 7
Fig. 7

Normalized change in grating reflectivity as a function of temperature θ (°C). The filled diamonds show values of R(23 °C) of 0.73, 0.73, 0.65, 0.45, 0.27, and 0.09 after grating annealing at θ = 100, 150, 200, 250, 300, 350 °C, respectively.

Fig. 8
Fig. 8

Comparison of experimental and calculated isothermal decays of gratings at three temperatures. The data are identical to those in Fig. 5, except that the experimental data have been corrected for the reversible change in grating reflectivity that results from heating of the fiber.

Fig. 9
Fig. 9

Plot of parameter C(t) as a function of ln(t), where t is the heating time for the curves in Fig. 2.

Fig. 10
Fig. 10

Calculated distribution of energy activation from the slope of the plot in Fig. 3. The symbols correspond to demarcation energies actually sampled by experiments.

Fig. 11
Fig. 11

Comparison of step isochronal decays of weak and strong unsaturated gratings. The initial grating reflectivity and the conditions of irradiance at the time of inscription are given in the inset.

Equations (6)

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

ηt, T=tanh-11-Tmint, T1/2tanh-11-Tmin01/2.
t2=k0T1/T2-1t1T1/T2
ηEd=11+expEd-E0kBT0=11+A0 expEdkBT0.
ηt, T=11+A0 expCtT.
Ct=1T0 lnk0+1T0 lnt.
NICC=11+0.000135 expCtT,

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