AUTOMATED PHOTOSENSITIVITY ENHANCEMENT IN OPTICAL FIBER TAPERS
Keywords:Fiber Bragg gratings, optical fiber taper, photosensitivity, flame-brush technique
An alternative technique that uses a flame-brush at high temperature to enhance UV light photosensitivity in an optical fiber is described. An extreme low-cost air aspirated propane-butane mini-torch is used, which produces a lower temperature flame than the one in the flame-brush original technique. It is shown that this change in the previous technique is also capable of improving photosensitivity and allowing the fiber Bragg grating imprinting process to be accelerated. Since the flame-brush photosensitivity enhancement process is designed to operate in an automated fiber taper rig, the process was evaluated in optical fiber tapers with different diameters. In this case, changes in photosensitivity are observed in the tapers in addition to the intrinsic photosensitivity occurring in the pristine fiber without being tapered.
A. Othonos and K. Kalli, Fiber Bragg Gratings: Fundamentals and Applications in Telecommunications and Sensing. Boston: Artech House, 1999.
J. Stone, "Photorefractivity in GeO2-doped silica fibres,`` J. Appl. Phys., vol. 62, no. 11, p. 4371, 1987.
F. Bilodeau, B. Malo, J. Albert, D. C. Johnson, K. O. Hill, Y. Hibino, M. Abe, and M. Kawachi, "Photosensitization of optical fiber and silica-onsilicon/silica waveguides,`` Opt. Lett., vol. 18, no. 12, pp. 953â€“955, 1993.
R. P. Kenny, T. A. Birks, and K. P. Oakley, "Control of optical fibre taper shape,`` Electronics Letters, vol. 27, pp. 1654â€“1656, 1991.
T. A. Birks and Y. W. Li, "The shape of fiber tapers,`` J. Lightwave Technol., vol. 10, no. 4, pp. 432â€“438, 1992.
J. Graf, P. V. de Barba, J. Dallmann, J. A. S. Lima, S. A. Teston, H. J. Kalinowski, and A. S. Paterno, "Fiber taper rig using a simplified heat source and the flame-brush technique,`` in SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC), vol. 5622, 2009, pp. 621 â€“ 624.
G. Brambilla, V. Pruneri, L. Reekie, and D. N. Payne, "Enhanced photosensitivity in germanosilicate fibers exposed to CO2 laser radiation`` Opt. Lett., vol. 24, no. 15, pp. 1023â€“1025, 1999.
G. Brambilla and V. Pruneri, "Enhanced photosensitivity in silicate optical fibers by thermal treatment`` Appl. Phys. Lett., vol. 90, issue 11, pp. 11905-1â€“3, 2007.
T. Erdogan, "Fiber grating spectra,`` J. Lightwave Technology, vol. 15, no. 8, pp. 1227â€“1294, 1997.
A. S. Paterno, J. C. C. Silva, M. S. Milczeswki, L. V. R. Arruda, and H. J. Kalinowski, "Radial-basis function network for the approximation of FBG sensor spectra with distorted peaks,`` Meas. Sci. Technol., no. 17, p. 1039-1045, 2006.
M. Douay, W. X. Xie, T. Taunay, P. Bernage, P. Niay, P. Cordier, B. Poumellec, L. D. J. R. Bayon, H. Poignant, and E. Delevaque, "Densification involved in the UV based photosensitivity of silica glasses,`` J. Lightwave Technol., vol. 15, no. 8, pp. 1329â€“1342, 1997.