Abstract
Two different sensing structures based on a hollow microsphere Fabry-Perot cavity are proposed. The hollow spheroidal cavities are fabricated resorting only to fusion splicing. The first structure is based on a hollow microsphere located at the fiber end and works as a probe sensor. The structure was subjected to lateral load pressure and presents a sensitivity of 1.56 +/- 0.01 nm/N. The second proposed sensor relies on an in-line hollow microsphere. The sensing structure allows the detection of lateral loading, with a sensitivity of 2.62 +/- 0.02 nm/N, as well as strain detection, with a sensitivity of 4.66 +/- 0.03 pm/mu epsilon. The two proposed sensors present similar response when subjected to temperature and have low thermal sensitivity.

Abstract
The concept of underwater docking stations has long been proposed to support the long term deployment of AUVs, but the number of successful solutions is still very disappointing. Hovering type AUVs can navigate arbitrarily slow, simplifying the docking maneuver and the requirements for the receiving structure. This paper describes a docking system that was developed to extend the mission duration of the MARES AUV, a man portable hovering type AUV. Given the wide range of operational scenarios and configurations of this AUV, one of the design requirements was to have a simple modular structure, that could easily be reconfigured to support different vehicle configurations, deployment scenarios and docking maneuvers. The paper provides details of the mechanical aspects, the onboard electronic subsystems, and the general operational procedure, as well as preliminary data from the first trials. © 2017 IEEE.

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