Acousto-optic properties of photonic crystal fibers

Photonic crystal fibers (PCFs) are a new class of optical fibers. They typically consist of a single glass material, such as pure silica, where the introduction of several air holes offers new optical properties compared to standard optical fibers. We report acoustic and acousto-optic experiments on this new fiber class. The phase velocity of the lowest order flexural acoustic mode is measured as a function of frequency for both a solid core and a hollow core photonic crystal fiber, and the results compared with those for a standard optical fiber. Acousto-optic interaction is used to measure the intermodal beat length between the lowest order and first higher order optical modes of the solid core PCF. The agreement between theory and experiments is very good.