The Brillouin scattering spectrum in a photonic crystal fiber (PCF) with a partially Ge-doped core is measured with a pump–probe technique at a wavelength of 1320 nm. One main peak and four subpeaks are observed. The main peak has a Lorentzian shape with the bandwidth Δν<sub>B</sub>=66MHz . Its intensity is six times higher than that from a standard single-mode fiber measured under the same conditions, which is consistent with the ratio of (1/A<sup>PCF</sup><sub>eff</sub>) /(1/A<sup>SMF</sup><sub>eff</sub>) , where A<sub>eff</sub> is the effective area of the fibers. The temperature coefficient for the main peak is 0.96 MHz/ °C. We believe that the subpeaks are caused by an interaction between light-wave and guided modes of longitudinal acoustic waves in the graded-Ge-doped region, the silica region, and the microstructured cladding. An analysis of the guiding and antiguiding properties of the PCF for acoustic waves is presented.
© 2003 Optical Society of AmericaPDF Article