Speckle statistics in a chaotic multimode fiber.

Wave chaos is devoted to the study of wave motion when the geometrical limit of rays is chaotic. Imprints of ray chaos may be found either in spectral and spatial properties of modes or in spatio-temporal evolution of wave packets. In this paper, we present a thorough experimental and theoretical analysis of field statistics for light propagating in a multimode fiber with a noncircular cross section. This optical fiber serves as a powerful tool to image waves in a system where light rays exhibit a chaotic dynamics. We show that, in the speckle regime, the experimentally measured statistical properties of intensity patterns are well accounted for by a "random Gaussian" hypothesis. A comparison is also made in the case of regular ray motion by using a circular optical fiber. Possible extensions and applications of the tools and concepts of wave chaos are mentioned in modern communication technology.