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

RF-over-fiber (RFoF) links with very high performance80 dB of spurious-free dynamic range (SFDR) in a 4-GHz instantaneous bandwidth, and noise figure = 10 dBwould impart tremendous benefits to submarine EW/SIGINT applications. RFoF link performance models that researchers at Photonic Systems, Inc. (PSI) have perfected over the last 25 years unfortunately indicate that neither linearized modulators nor coherent detection (the most frequently proposed approaches to high-SFDR links) will enable an RFoF link to exhibit the desired performance. In the approach that PSI proposes to develop for this SBIR program, high SFDR is enabled by a novel integrated electronic linearization circuit, and low noise figure is enabled by suppressing the relative intensity noise (RIN) outside a narrow band surrounding the optical carriers from multiple, wavelength-multiplexed semiconductor lasers. The fact that this approach leverages conventional photonic compoents, and the great extent to which these components can ultimately be integrated, imparts an inherently high degree of modularity and low recurring-engineering cost to links that use the proposed approach. Phase I of the proposed program will include a proof-of-concept demonstration at low frequency, and Phase II will culminate in demonstration of an RFoF link that meets all the above performance specifications.