Quasi-Phase Matched Waveguides for Quantum Frequency Conversion

This Phase I SBIR effort will examine the feasibility of fabricating 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 I effort, coupling and propagation loss will be modeled and measured to determine the limits of losslessness in anti-reflection (AR) coated KTP and LN waveguides. The Phase I will also investigate a versatile fiber microbench platform for optimized mode matching, compact and robust fiber packaging, and noise and spectral filtering. Optical and material models will be used to predict end-to-end performance to determine the feasibility of using fiber-packaged KTP and LN waveguides to deliver quantum frequency convertors meeting future provably-secure DoD communications needs.