A wide band electro-optic modulator is presented which allows the frequency
calibration of Brillouin spectra over the frequency range from a few MHz u
p to approximate to 40 GHz, a range spanning Brillouin light scattering fro
m condensed matter. Measurements of both frequency and the linewidth of Bri
llouin peaks relative to longitudinal acoustic modes of water using the ele
ctro-optic modulator as a frequency reference are presented. (C) 2001 Ameri
can Institute of Physics.