Pressure Resistant Bulkhead Penetrators for Fiber Optics in Deep Ocean Applications

Abstract

This paper describes results obtained at the Naval Ocean Systems Center, San Diego, under Independent Exploratory Development funding. The objective was to develop a robust, fully-demountable, high pressure penetrator design suitable for coupling light signals transmitted by optical fiber elements in an undersea cable operated at high ambient hydrostatic pressure into an electronics package or manned space. The feasibility of constructing such penetrators utilizing Graded Refractive INdex (GRIN) rod lenses as combination pressure barriers and imaging devices was demonstrated. Prototype realizations exhibited excellent optical throughput performance and readily survived in excess of 10,000 psi pressure differential as well as tolerating a wide temperature range. The design lends itself to hermetic construction for applications requiring no vapor diffusion over long mission durations. Such devices exhibit excellent potential for satisfying SUBSAFE requirements for manned submersible applications.