Studies are continuing on the use of long, low‐loss optical fibers as direct acoustic sensors [J. A. Bucaro, E. F. Carome, and M. R. Layton, J. Acoust. Soc. Am.62, S72 (1977)]. Currently we are employing a single‐path coiled‐fiber system and examining in detail acoustically induced variations in the transmitted light intensity. We have detected effects that we attribute to changes in the intensity of the light propagated in a particular fiber mode. Details of the experimental technique employed and quantitative data on these effects will be presented. [Supported in part by Office of Naval Research.]