image: Shayan Mookherjea, leading a team of researchers at the University of California, San Diego, designed and fabricated a multi-component photonic integrated circuit that includes structures such as couplers, micro-resonators, interferometers, filters, signal splitters and combiners, electronic diodes and heaters. Their work miniaturized a bulky, table-top optical apparatus into a small, stable, electronically controllable silicon microchip.
Mookherjea and colleagues are now beginning an NSF project to develop photonic microchips that can transmit secure communications over conventional optical fiber through quantum entanglement.
Credit: Shayan Mookherjea, UC San Diego
To advance the technology necessary for secure communication, the National Science Foundation (NSF) has awarded $12 million to develop systems that use photons in pre-determined quantum states as a way to encrypt data.
Directed by NSF's Office of Emerging Frontiers and Multidisciplinary Activities (EFMA), the awards signal a major investment in quantum information science, one of NSF's 10 Big Ideas for long-term discovery and innovation.
"Investments in frontier, and potentially transformative, fundamental science and engineering research, such as quantum communication, are essential to compete in the global innovation economy," said Sohi Rastegar, head of EFMA.
Researchers have long sought to encode photons -- minute particles of light -- with information that could travel through fiber optic cables across vast distances, and that would be immutably linked to a photon counterpart on the other end, a phenomenon known as quantum entanglement. A stream of encrypted data would follow behind each encoded photon.
Any attempt to intercept, tamper with or divert the data would alter the entangled photon's quantum state and become evident on arrival at its destination. If a compromised photon is detected, the quantum key needed to unlock the encryption no longer works, and the communication remains secure.
As the demand for better cybersecurity increases, NSF will support six interdisciplinary teams consisting of 26 researchers at 15 institutions to perform potentially transformative, fundamental research under the Advancing Communication Quantum Information Research in Engineering (ACQUIRE) research area in the NSF Directorate for Engineering's Emerging Frontiers in Research and Innovation (EFRI) program. Established in 2007, EFRI seeks to inspire and enable researchers to expand the limits of knowledge in the service of grand engineering challenges and national needs.
ACQUIRE researchers will confront major challenges in a four-year quest to engineer a quantum communication system on a chip. The chip will need to operate at room temperature with low energy in a fiber optic network with entangled photons.
Currently, such a communication system may be demonstrated in laboratories, but only at cryogenic -- very low -- temperatures, and with bulky, energy-intensive equipment. However, a fundamental understanding of quantum physics and optical materials, as well as recent progress in nanoscale photonic integration, have brought communication systems scaled to the quantum level within reach.
If successful, the ACQUIRE teams' results will begin to realize the hardware needed for secure and efficient quantum communication. The findings from the ACQUIRE projects will also advance quantum sensing and computing.
"A growing interest in quantum photonics and a new understanding of quantum physics and nanomaterials make this the perfect time to pursue significant engineering advances in quantum communication," said Dominique Dagenais, the NSF program director who coordinated the ACQUIRE projects.
The exciting promise of quantum information science is described in the July 2016 National Science and Technology Council report, Advancing Quantum Information Science: National Challenges and Opportunities.
The following researchers will lead the six EFRI teams pioneering quantum communication systems:
- Dirk Englund, Massachusetts Institute of Technology, Scalable quantum communications with error-corrected semiconductor qubits.
- Kai-Mei Fu, University of Washington, An integrated quantum communication transmission node.
- Alexander Gaeta, Columbia University, Development of heterogenous platform for chip-based quantum information applications.
- Qiang Lin, University of Rochester, A scalable integrated quantum photonic interconnect.
- Shayan Mookherjea, the University of California-San Diego, Microchip photonic devices for quantum communication over fiber.
- Hong Tang, Yale University, Integrated nanophotonic solid state memories for telecom wavelength quantum repeaters.
The Fiscal Year 2016 EFRI ACQUIRE topic was developed with significant input from the research community and in close collaboration with the following three NSF directorates: Engineering, Computer and Information Science and Engineering, and Mathematical and Physical Sciences.
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