High-resolution microwave phonon spectroscopy of dispersion-shifted fiber

First measurements of acoustic modes in dispersion-shifted fiber are presented. High-resolution microwave phonon spectroscopy, performed using an improved method for resolving resonant spectral features, reveals the presence of the L/sub 04/ mode. The use of external cavity tunable lasers for pump and probe enables kilohertz range spectral resolution and high sensitivity. In addition, this method enables down conversion of the phonon spectrum to lower frequencies through the use of beat-Brillouin effect.