Dr. John D. Lekki Profile

Dr. John D. Lekki

Electronics Engineer at NASA Glenn Research Ctr

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Publications (15)

Proceedings Article | 13 March 2024 Presentation + Paper

Overview of NASA’s quantum metrology laboratory and quantum communications analysis suite for degenerate source verification and validation within aerospace network applications

Evan Katz, Adam Fallon, Yousef Chahine, Ian Chin, Ian Nemitz, Bryan Welch, John Lekki

Proceedings Volume 12911, 1291105 (2024) https://doi.org/10.1117/12.3009164

KEYWORDS: Quantum networks, Quantum measurement, Quantum entanglement, Quantum modeling, Quantum sources, Quantum channels, Quantum communications, Quantum processes

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Proceedings Article | 8 March 2023 Presentation + Paper

Dual fiber spectrometer for highly non-degenerate entanglement source

Adam Fallon, Daniel Hart, Evan Katz, Brian Vyhnalek, Ian Chin, John Lekki

Proceedings Volume 12446, 124460X (2023) https://doi.org/10.1117/12.2650914

KEYWORDS: Quantum entanglement, Spectroscopy, Quantum sources, Quantum networks, Quantum correlations, Dispersion

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Proceedings Article | 5 March 2021 Presentation + Paper

An overview of key optical communications technologies under development at the NASA Glenn Research Center

Félix Miranda, Sarah Tedder, Brian Vyhnalek, Jennifer Downey, Adam Wroblewski, Casey Bakula, Evan Katz, John Lekki, Rachel Dudukovich, Alan Hylton, Daniel Raible, Robert Romanofsky

Proceedings Volume 11692, 116920X (2021) https://doi.org/10.1117/12.2579420

KEYWORDS: Aerospace engineering, New and emerging technologies, Space operations, Data communications, Telecommunications, Quantum key distribution, Mobile communications, Video, Space robots, Robotics

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Proceedings Article | 4 March 2019 Paper

Bell inequality experiment for a high brightness time-energy entangled source

Ian Nemitz, Jonathan Dietz, Evan Katz, Brian Vynhalek, Benjamin Child, Bertram Floyd, John Lekki

Proceedings Volume 10902, 109021U (2019) https://doi.org/10.1117/12.2509849

KEYWORDS: Interferometers, Visibility, Single photon, Fiber optics, Mach-Zehnder interferometers, Photodetectors, Quantum communications, Particles, Single mode fibers, Waveguides

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Proceedings Article | 4 March 2019 Paper

Studies on a time-energy entangled photon pair source and superconducting nanowire single-photon detectors for increased quantum system efficiency

Evan Katz, Benjamin Child, Ian Nemitz, Brian Vyhnalek, Tony Roberts, Andrew Hohne, Bertram Floyd, Jonathan Dietz, John Lekki

Proceedings Volume 10910, 1091015 (2019) https://doi.org/10.1117/12.2508736

KEYWORDS: Sensors, Nanowires, Silicon, Avalanche photodetectors, Photodetectors, Quantum efficiency, Single photon detectors, Superconductors, Time correlated photon counting, Signal to noise ratio

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Time-energy entangled photon pairs are created by a system consisting of a 1064 nm pump diode laser that is fiber coupled to a high generation rate photon pair source. The source is a dual element periodically poled Magnesium Oxide doped Lithium Niobate (MgO:LN) waveguide that upconverts 1064 nm photons to single 532 nm photons in the first stage. In the second stage, the green photons are down converted to time-energy entangled photon pairs at 794 nm and 1614 nm. The output photon pairs are guided by fiber to sorting optics where they are separated and sent into high-efficiency photon detectors. In particular, the 1614 nm photons are detected by a superconducting nanowire with efficiency near 85% and dead time less than 30 ns. Detector output electrical signals are sent to a time tagger with bin resolution as narrow as 25 ps for coincidence counting. The ultimate goal of this setup is to demonstrate a single-source, high efficiency, high data rate, low noise, quantum communication system to enable Earth-space quantum networks. Test results that characterize the time-energy entangled photon pair creation rates of our source will be presented, via measures of accidental and true coincidence rates versus pump current. To reduce noise (accidentals) as much as possible, and for better understanding of our overall quantum system path-efficiency, studies of fluorescence caused by our pump’s 1064 nm and 532 nm photons will be investigated and discussed. Finally, characteristic measurements of our superconducting nanowire detector, such as dead time and detection efficiency versus electrical bias, will be offered. Please verify that (1) all pages are present, (2) all figures are correct, (3) all fonts and special characters are correct, and (4) all text and figures fit within the red margin lines shown on this review document. Complete formatting information is available at http://SPIE.org/manuscripts Return to the Manage Active Submissions page at http://spie.org/submissions/tasks.aspx and approve or disapprove this submission. Your manuscript will not be published without this approval. Please contact author_help@spie.org with any questions or concerns.

Proceedings Article | 29 January 2018 Paper

Coincidence studies of entangled photon pairs using nanowire detection and high-resolution time tagging for QKD application

Evan Katz, Nathaniel Wilson, Ian Nemitz, Sarah Tedder, Brian Vyhnalek, Bertram Floyd, Tony Roberts, Pushkar Pandit, Skyler Baugher, Roger Tokars, John Pouch, John Lekki

Proceedings Volume 10559, 1055905 (2018) https://doi.org/10.1117/12.2288474

KEYWORDS: Quantum efficiency, Sensors, Signal to noise ratio, Quantum key distribution, Photodetectors, Nanowires, Quantum communications, Picosecond phenomena

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Proceedings Article | 13 September 2016 Paper

Free-space quantum key distribution with a high generation rate potassium titanyl phosphate waveguide photon-pair source

Jeffrey Wilson, Dalton Chaffee, Nathaniel Wilson, John Lekki, Roger Tokars, John Pouch, Tony Roberts, Philip Battle, Bertram Floyd, Alexander Lind, John Cavin, Spencer Helmick

Proceedings Volume 9980, 99800U (2016) https://doi.org/10.1117/12.2237742

KEYWORDS: Quantum key distribution, Waveguides, Ferroelectric materials, Semiconductor lasers, Photons, Sensors, Signal to noise ratio, Modulation, Polarization, Indium gallium arsenide

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SPIE Journal Paper | 1 October 2009

Glenn Research Center quantum communicator receiver design and development

Murad Hizlan, John Lekki, Binh Nguyen

OE, Vol. 48, Issue 10, 105003, (October 2009) https://doi.org/10.1117/12.10.1117/1.3241989

KEYWORDS: Receivers, Quantum communications, Optical communications, Field programmable gate arrays, Error analysis, Optical engineering, Telecommunications, Clocks, Photons, Data communications

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Proceedings Article | 8 April 2009 Paper

NDE using sensor based approach to propulsion health monitoring of a turbine engine disk

Ali Abdul-Aziz, Mark Woike, G. Abumeri, John Lekki, George Baaklini

Proceedings Volume 7295, 729505 (2009) https://doi.org/10.1117/12.815494

KEYWORDS: Failure analysis, Nondestructive evaluation, Sensors, Finite element methods, Safety, Mechanics, Data modeling, Inspection, Analytical research, Image filtering

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SPIE Journal Paper | 1 May 2008

Mode sorter and detector based on photon orbital angular momentum

Baha Jassemnejad, A. Bohannan, John Lekki, Kenneth Weiland

OE, Vol. 47, Issue 05, 053001, (May 2008) https://doi.org/10.1117/12.10.1117/1.2931686

KEYWORDS: Computer generated holography, Mach-Zehnder interferometers, Interferometers, Spatial light modulators, Prisms, Fluctuations and noise, Sensors, Photodetectors, Telecommunications, CCD cameras

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SPIE Journal Paper | 1 January 2008

Quantum entanglement enables low-power optical communication to orbital ranges

John Lekki

OE, Vol. 47, Issue 01, 015003, (January 2008) https://doi.org/10.1117/12.10.1117/1.2835043

KEYWORDS: Photons, Receivers, Optical communications, Transmitters, Quantum communications, Nonlinear crystals, Telecommunications, Optical engineering, Collimation, Signal generators

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Proceedings Article | 2 August 2004 Paper

Single-photon nondiffracting Bessel beams

John Lekki, Quang-Viet Nguyen, Marc Seibert, Kenneth Weiland, James Williams

Proceedings Volume 5531, (2004) https://doi.org/10.1117/12.562570

KEYWORDS: Bessel beams, Photon counting, Diffraction, Bessel functions, Helium neon lasers, Single photon, Photodetectors, Photonic crystals, Beam propagation method, Superposition

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SPIE Journal Paper | 1 February 2003

Detection sensitivity optimization of optical signals generated by fiber optic Bragg gratings under dynamic excitation

Grigory Adamovsky, John Lekki, James Lock

OE, Vol. 42, Issue 02, (February 2003) https://doi.org/10.1117/12.10.1117/1.1534593

KEYWORDS: Interferometers, Optics manufacturing, Signal detection, Fiber Bragg gratings, Fiber optics, Sensors, Ferroelectric materials, Mirrors, Signal generators, Michelson interferometers

Proceedings Article | 15 July 2002 Paper

Evaluation of mechanical modal characteristics using optical techniques

John Lekki, Grigory Adamovsky, Patrick Flanagan, Kenneth Weiland

Proceedings Volume 4701, (2002) https://doi.org/10.1117/12.474652

KEYWORDS: Sensors, Fiber optics sensors, Holograms, Holography, Fiber Bragg gratings, Copper, Demodulation, Fiber optics, Photodiodes, Aerospace engineering

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Proceedings Article | 6 August 2001 Paper

Demodulation system for fiber optic Bragg grating dynamic pressure sensing

John Lekki, Grigory Adamovsky, Bertram Floyd

Proceedings Volume 4328, (2001) https://doi.org/10.1117/12.435517

KEYWORDS: Sensors, Signal processing, Fiber Bragg gratings, Interferometers, Fiber optics, Fiber optics sensors, Mirrors, Demodulation, Ferroelectric materials, Sensing systems

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Showing 5 of 15 publications

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