Quantum Communication Circuits on a CMOS Chip (QC4)

University Of California-San Diego, La Jolla CA

Investigators

Abstract

The emergence of Internet of Things increasingly involves transmission of confidential and secret data such as financial transactions, medical files, and data related to national security. These applications have increased the need for privacy and authentication in future data networks. Traditional encryption tools rely for their security on computational intractability of mathematical procedures such as factoring large numbers, and are therefore, in principle vulnerable. This vulnerability is absent in quantum optics technologies that have been explored during the past few decades. However, in current approaches, quantum networks exploit the most obvious independent quantum point-to-point transmission links between different nodes, making scaling up quantum networks increasingly complicated. Moreover, the technology for quantum networks uses realizations based on free space optics and/or hybrid systems combining free space with fiber optics. These approaches, however, do not scale; they are bulky, and cannot handle the high level of complexity in a network with a large number of nodes. The vision of this project is to develop quantum communication circuits on a silicon photonic chip to meet the societal needs of future quantum networks, exploiting multiple entangled and single-photons carrying qubits. Specifically, this proposal is focused on the experimental realization and theoretical analysis of quantum material sources, devices and circuits manufactured with CMOS technology for scalable quantum secret sharing network. The proposed research on exploiting multiple energy-entangled and single qubit carrying photons will enable the construction of next generation quantum networks with unprecedented impact on cybersecurity. The project will provide scientific training in quantum optics for students at graduate and undergraduate levels as well as serve as a platform for outreach, education and collaborative efforts with middle and high schools. Technical description To meet the needs of next generation quantum networks for cybersecurity, this project is focused on experimental realization and analysis of a quantum secret sharing network utilizing nodes capable of generating time-bin entangled triplets via a down-conversion nonlinear process in the silicon nitride material platform. The generated multiple photons are used to prepare high-fidelity heralded single photons, Greenberger-Horne-Zeilinger (GHZ) time-bin entangled states and remote entanglement states in support of a true network topology in contrast to commonly used two-photon entanglement supporting point-to-point links. To construct such a network we will develop novel quantum optical devices and components on a chip exploiting CMOS processes with use of fabrication foundries. Therefore, the goal of this proposal is to carry out a comprehensive approach in construction and experimental validation of quantum communication devices, components and circuits on a CMOS compatible chip for quantum secret sharing network. The specific objectives include analysis, design, fabrication, testing and demonstration of (i) generation of triplet time-bin entangled photons to create high fidelity heralded single photons, (ii) preparation of GHZ states, (iii) preparation of remote entanglement states on a chip, (iii) demonstration of quantum detection circuit on a chip, and (iv) demonstration of quantum relay circuit on a chip. The proposed research is transformative in nature as it will not only mark the first step toward integration of inexpensive and compact quantum communication circuits on a chip, but also offer a route to practical realization of quantum communication network systems in support of future societal need in cybersecurity. The project will provide scientific training in quantum optics and quantum communications for students at graduate and undergraduate levels as well as serve as a basis for outreach, education and collaborative efforts with middle and high schools. Engagement of students of diverse ethnicity, gender and economic backgrounds in Science, Technology, Engineering and Mathematics (STEM) will be continued via the ongoing RET, REU, and COSMOS activities. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.