Guided acoustic-wave Brillouin scattering with optical pulses.

Both continuous-wave and pulsed laser sources have been used to study guided acoustic-wave Brillouin scattering (GAWBS) in optical fibers. Measurements of the scattering process with either a multimode or single-frequency cw source produced similar GAWBS rf spectra. However, with mode-locked pulses the GAWBS rf spectrum extends over a larger frequency range owing to the heterodyning of the laser harmonics with the scattered light. This effect is illustrated by using two mode-locked lasers with different pulse repetition rates of 76 and 980 MHz.