Theoretical and experimental investigation of Brillouin scattering for the generation of millimeter waves

We investigate and discuss stimulated Brillouin scattering in optical fibers for the generation of millimeter waves in theory and experiment. With a derivation of the responsible differential equation system we show that the phases of two independently amplified sidebands of a frequency comb will remain the same. Neither third-order nonlinear effects like self- and cross-phase modulation nor the Brillouin amplification has an influence on the phases. We verify our theoretical predictions with phase noise measurements of the generated millimeter-wave signal. The results show that the generated phase noise is in fact very low.