Radio Frequency over Fiber (RFoF) for the Next Generation Submarine Electronic Warfare (EW) System

Submarine applications for antennas are severely constricted by mission constraints for stealth and force protection. High fidelity fiber optic links could potentially open a new range of mission capabilities by enabling towed antenna arrays that could be accessed while submerged. However, to date RF photonic links have had insufficient noise performance and/or dynamic range to satisfy these mission requirements. To this end, PSI proposed a series of component and link architecture developments that will provide improved performance over the existing state of the art. Specifically, PSI will utilize its expertise in high bandwidth lithium niobate modulators and high-linearity MUTC photodiodes to establish a baseline of performance that can be achieved using traditional link architectures that exceeds existing commercial solutions. This effort will be dovetailed with explorations into optically downconverted links that utilize injection locked lasers to convert the received frequency down to baseband directly in the optical domain, where very high photocurrent detectors can be used for enhanced link performance. Furthermore, vertically integrated optical phase locked loop receivers with delays times on the order of femtoseconds will be explored to realize high dynamic range links with phase feedback that have previously been limited in dynamic range improvement and operational bandwidth.