Use of a fiber-optic cable with a free-fall microstructure profiler

A new free-fall microstructure profiler has been developed which uses a thin, flexible fiber-optic cable to transmit data to the ship. The Advanced Microstructure Profiler (AMP) is designed to perform rapid and repetitive profiling to depths of 300 m, and thus must have a cable that permits instrument retrieval and data transmission at high rates to sample the microstructure adequately. To avoid cable-induced contamination of the measurements, AMP must operate essentially as a free-fall device and the cable must offer very low drag during descent. Experience during the past year has shown that a fiber-optic data link encased in a Kevlar strength member achieves these goals. This paper gives a brief description of AMP and its fiber-optic data link and discusses some operational experiences in its utilization.