Quasi-Phase Matched Waveguides for Quantum Frequency Conversion

This Phase II SBIR effort will fabricate quantum frequency conversion (QFC) devices with cutting-edge performance to satisfy DARPA quantum information science applications. Quasi-phase matching (QPM) in potassium titanyl phosphate (KTP) and lithium niobate (LN) waveguides designed for very low loss will be used to create frequency convertors at arbitrary source and target wavelengths with near-unity efficiency and low background noise. In the Phase II effort, coupling and propagation loss will be reduced in anti-reflection (AR) coated KTP and LN waveguides and a versatile fiber microbench platform for optimized mode matching, compact and robust fiber packaging, and noise and spectral filtering will be developed. Fiber-packaged KTP and LN waveguides will be used to develop robust packaged quantum frequency convertors with near-unity internal quantum efficiency (QE) and estimated 1.0 dB end-to-end loss in order to address future provably-secure DoD communications and other quantum information needs.