Subpeaks in the Brillouin loss spectra of distributed fiber-optic sensors were observed for what is believed to be the first time and studied. We discovered that the Fourier spectrum of the pulsed signal and the off-resonance oscillation both contributed to subpeaks. The off-resonance oscillation at frequency |nu - nu_B| is the oscillation in the Brillouin time domain when beat frequency nu of the two counterpropagating laser beams does not match local Brillouin frequency nu_B. This study is important in differentiating the subpeaks from actual strain-temperature peaks.
© 2005 Optical Society of America
(060.2310) Fiber optics and optical communications : Fiber optics
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(190.5890) Nonlinear optics : Scattering, stimulated
(290.5830) Scattering : Scattering, Brillouin
(290.5900) Scattering : Scattering, stimulated Brillouin
Yidun Wan, Shahraam Afshar V., Lufan Zou, Liang Chen, and Xiaoyi Bao, "Subpeaks in the Brillouin loss spectra of distributed fiber-optic sensors," Opt. Lett. 30, 1099-1101 (2005)