Career Fair and Career Events

Title: Engineering of Photon Entanglement in Integrated Quantum Optical Devices Presenter: John W. Snyder Date: December 14, 2017 Time: 11:00 AM Location: PHO 339 Advisor/Chair: Alexander Sergienko (ECE) Committee: Anna Swan (ECE/Physics/MSE), Siddharth Ramachandran (ECE/MSE), Roberto Paiella (ECE/MSE) Abstract: Through the generation and manipulation of light at the single photon level, the unique properties of quantum mechanics may be leveraged for technological purposes. Quantum entanglement, the phenomenon where multiple particles exist in a non-factorizable state, is at the center of several applications including encrypted communications, high-resolution imaging, and uniquely powerful computational systems—all of which feature special advantages over comparable classical systems. The nonlinear quantum optical process of spontaneous parametric downconversion, or SPDC, is one method for producing correlated photon pairs that can be subsequently entangled. Waveguides in a nonlinear optical medium, such as lithium niobate, may be engineered to facilitate SPDC at a specific wavelength. By inverting the ferroelectric domains in a periodic pattern along the propagation direction of the waveguide, a target nonlinear interaction is phase matched. This process is called periodic poling, and is a powerful tool for engineering nonlinear and quantum optics. The proposed thesis consists of the design, simulation, fabrication, and characterization of a uniquely configured titanium-diffused periodically poled lithium niobiate (Ti:PPLN) device currently in development. This device is intended to generate two collinearly propagating entangled photon pairs via two consecutive SPDC interactions, which may then be hyperentangled in both frequency and polarization. Full simulations have been conducted for the spectra and expected photon counts of the relevant nonlinear interactions. Technological improvements to the fabrication process, most notably a custom-designed high-speed FPGA-based control system for high voltage poling of fine structures, are also demonstrated. Future work will consist of optical testing and further refinement of device fabrication methodology. Ultimately these devices will be incorporated with ancillary structures such as beam splitters and polarization rotators in order to realize more fully integrated quantum optical systems for entanglement swapping and Bell tests on a chip as major elements of quantum communication and networking protocols.