Fig. 1. BDG excitation and detection

Fig. 2. Distribution of the acoustic mode

Fig. 3. Reflection spectrum of Brillouin dynamic grating

Fig. 4. Reflection spectrum by Brillouin frequency shift and Doppler shift

Fig. 5. Temporal and spatial distribution of refractive index perturbation

Fig. 6. Reflection spectrum of different pump power

Fig. 7. Peak reflectivity as a function of pump power

Fig. 8. Reflection spectrum of different pulse width

Fig. 9. The spectral width and the peak reflectivity as a function of pump pulse width

Fig. 10. Reflection spectrum of core diameter

Fig. 11. Peak reflectivity as a function of core diameter