Enhancing the measurement range of a Brillouin-based fiber optic distributed-temperature sensor by improving receiver sensitivity through optical preamplification

We report on the use of a cost-effective erbium-doped based optical preamplifier in a single-ended distributed fiber-optic sensor to improve receiver sensitivity and hence measurement range. The improved accuracy of spontaneous Brillouin measurements was demonstrated in a 23km sensor and was limited by amplified spontaneous emission from the preamplifier, which was verified theoretically. Reduction of amplified spontaneous emission was achieved with a 0.37nm in-fiber Bragg grating. A signal-to-noise improvement of 17dB was achieved and supported by theory, which translates to approximately 40km range improvement for a single-mode sensing fiber having losses of 0.2dB/km at 1550nm.

[1]  T. Parker,et al.  A fully distributed simultaneous strain and temperature sensor using spontaneous Brillouin backscatter , 1997, IEEE Photonics Technology Letters.

[2]  Y. Tachikawa,et al.  Noise characteristics of Er/sup 3+/-doped fiber amplifiers pumped by 0.98 and 1.48 mu m laser diodes , 1990, IEEE Photonics Technology Letters.

[3]  David N. Payne,et al.  Efficient erbium-doped fiber amplifiers incorporating an optical isolator , 1995 .

[4]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[5]  Y Azuma,et al.  Brillouin gain variation due to a polarization-state change of the pump or Stokes fields in standard single-mode fibers. , 1989, Optics letters.

[6]  N. A. Olsson,et al.  Characteristics of a semiconductor laser pumped brillouin amplifier with electronically controlled bandwidth , 1987 .

[7]  M. Okayasu,et al.  Erbium-doped fibre amplifiers with an extremely high gain coefficient of 11.0 dB/mW , 1990 .

[8]  M. O'Mahony.  Semiconductor laser optical amplifiers for use in future fiber systems , 1988 .

[9]  Diode-pumped Landau-Placzek based distributed temperature sensor utilising an all-fibre Mach-Zehnder interferometer , 1996 .

[10]  E. Desurvire.  Erbium-doped fiber amplifiers , 1994 .

[11]  T. Horiguchi,et al.  Tensile strain dependence of Brillouin frequency shift in silica optical fibers , 1989, IEEE Photonics Technology Letters.

[12]  R. Laming,et al.  Theoretical modeling of erbium-doped fiber amplifiers with excited-state absorption. , 1989, Optics letters.

[13]  P. W. Black.  Optical fibre communications — principles and practice , 1986 .

[14]  M. Nishimura,et al.  Erbium-doped fiber amplifier pumped at 1.48 mu m with extremely high efficiency , 1991, IEEE Photonics Technology Letters.

[15]  Winfield Hill,et al.  The art of electronics - Second edition , 1989 .

[16]  R. Howard,et al.  On the noise of high-transimpedance amplifiers for long-wavelength pulse OTDRs , 1987 .

[17]  M. Gold,et al.  Design of a long-range single-mode OTDR , 1985 .