Advances in Fiber Optic Microtethered Systems for Deep-Sea Sensing and Exploration

The field of deep-sea oceanographic research is commonly restricted to large research vessels and bulky underwater equipment requiring complex deployment schemes. Most equipment is in some way tethered to the deployment vessel, apart from fully autonomous systems. Typical tethers are heavily reinforced industrial grade cables, supplying power and communication to the subsea payloads. By utilizing fiber optic microtethers, specifically Fiber Optic Fishing Line (FOFL), small profile oceanographic sensor payloads and remote operated vehicles (ROVs) can be deployed from any size vessel of opportunity with minimal resources. The goal of developing these tethers further is to not replace, but operate alongside current reliable research methods, enabling deep-sea access to the ocean for a broader community of scientists and students. Here we present our improvements on FOFL, the Fiber Optic Reel System (FOReelS), and various sensing payloads designed to be deployable with FOFL on the FOReelS. We present performance data of the opto-mechanical properties of the microtether, alongside the successful development and deployment of three static modular payloads and two mobile ROVs in the field.