Quantum frequency conversion for quantum communication

In the burgeoning field of quantum information science, the states of individual photons, or entangled photon pairs, are used for storage, processing and secure transmission of information.The single photon sources and detectors used in this field perform best in the near-infrared (750-1000 nm) wavelength range.However, for long-distance transmission over optical fiber, it is necessary to take advantage of the minimum-loss windows around 1300 nm and 1500 nm. Thus, a crucial element in a quantum optical information processing system is a quantum frequency conversion device that can convert photons between these disparate wavelength bands while preserving their quantum state.SRICO proposes to develop a plug-and-play nonlinear device for quantum frequency conversion based on periodically poled lithium niobate (PPLN) waveguide having high difference and sum conversion efficiency greater than 30% per Watt per centimeter square with at least 10 dB signal-to-noise performances. Two complimentary modules will be developed for this proposal: (1) Difference Frequency Generation (DFG) module with input wavelengths of 795 nm and 1989 nm and (2) Sum Frequency Generation (SFG) module with inputs of 1324 nm and 1989 nm. The Phase I will design robust, fully packaged SFG and DFG quantum frequency conversion modules incorporating the PPLN waveguide device, coupling optics and temperature control apparatus. The overall size of the modules will be less than 30 cubic centimeter. In the Phase I Option task, PPLN waveguide devices will be fabricated and validated in a laboratory setting to demonstrate the key characteristics of the QFC modules.