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Reilly D.R.,NuCrypt LLC | Kanter G.S.,NuCrypt LLC
Optics Express | Year: 2014

High speed and high sensitivity time-of-flight lidar is demonstrated by judiciously choosing the repetition rates of a pulsed optical source and the gate rate of a GHz gated single photon detector. Sub-mm ranging can be performed in sub-ms time scales at low received powers. We also demonstrate a method to extend the unambiguous measurement range by simultaneously transmitting multiple optical pulse rates and measuring the return signal with a single detector. © 2014 Optical Society of America.


Reilly D.R.,NuCrypt LLC | Wang S.X.,NuCrypt LLC | Kanter G.S.,NuCrypt LLC
IEEE Photonics Technology Letters | Year: 2012

An optical analog-to-digital converter that uses pulses of multiple wavelengths to nonuniformly sample a microwave signal is used to determine an input microwave frequency to a high accuracy over a large frequency range. Measurement times of 4 s lead to frequency errors of ∼ 300 Hz over a measurement range of 10-18 GHz. We also identify the frequency and magnitude of multiple microwave inputs. The simple configuration is robust and practical. © 2012 IEEE.


Kanter G.S.,NuCrypt LLC
Optics InfoBase Conference Papers | Year: 2010

We describe the state of physics-based secure optical communication systems. Practical issues associated with both key generation and high-speed physical-layer secure data transmissions are discussed. © 2010 Optical Society of America.


Wang S.X.,NuCrypt LLC | Chan C.,NuCrypt LLC | Moraw P.,NuCrypt LLC | Reilly D.R.,NuCrypt LLC | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We generate time-bin entangled photons and measure the resulting quantum state with a tomography system that uses asymmetric interferometers having 3×3 output couplers. This configuration allows for measurements to be made simultaneously in all bases that are required for tomographic reconstruction. By eliminating the burden of tuning interferometer phases and by measuring all the spatial and temporal modes, substantial improvements in measurement speed are observed. Raw fidelities of 84% with respect to an ideal entangled state are measured in about 2 s using a 12-MHz entangled state generator, with corresponding accidental count subtracted fidelities exceeding 90%. © 2012 American Physical Society.


Liu J.,Northwestern University | Kanter G.S.,NuCrypt LLC | Wang S.X.,NuCrypt LLC | Kumar P.,Northwestern University
Optics Communications | Year: 2012

We report on a high rate, ultra-low timing jitter, short optical pulse generator based on cascaded amplitude and phase modulation in an optoelectronic oscillator. The radio-frequency supermodes are shown to be greatly suppressed with the dual-loop architecture, and a highly coherent and flat optical frequency comb is generated. Optical pulses of 12.8 ps duration are obtained with 27.5 fs integrated timing jitter from 100 Hz to 10 MHz. © 2011 Elsevier B.V. All rights reserved.


Grant
Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase II | Award Amount: 374.99K | Year: 2013

Detecting light at the single photon level is a fundamental measurement function that is useful in a wide variety of applications, including such diverse fields as quantum communications, laser ranging, and biological spectroscopy. Avalanche photodiode based single-photon detectors are convenient solid-state devices that do not require cryogenic cooling. We will build avalanche photodiode based single-photon-detection systems that make use of advanced gating techniques to improve their count rate. The single-photon detectors will be used in quantum measurement, such as entanglement distribution, and lidar applications. We will also use nonlinear frequency conversion to enable improved single-photon detectors in the telecom-wavelength bands around 1.3 and 1.5 microns.


Grant
Agency: Department of Defense | Branch: Air Force | Program: STTR | Phase: Phase II | Award Amount: 749.99K | Year: 2012

ABSTRACT: Quantum key distribution (QKD) is an exciting application of quantum theory to the important real-world problem of secure communication. Specifically, QKD may allow for provably secure key distribution. These random keys can then be used either in a one-time pad style encryption system (for absolute security at low rates) or a standard encryption system (for high security at high rates). Traditional means of distributing keys are not provably secure. The value of QKD thus rests in its unprecedented high level of security, so it is critical to maintain the integrity of the theoretical security advantage in any actual implementation. In practice, issues associated with non-ideal components and with information leakage from the classical communication channel required between the legitimate users can make it very difficult to guarantee security, or can have performance implications such as reducing the maximum key distribution distance. We will design and build a new type of QKD protocol that reduces the amount of classical communication required leading to new and more robust security models as well as greater efficiency. Quantum tools including a high speed single photon detection system and a source of entangled light will be developed to implement the protocol in an efficient way. BENEFIT: The technologies investigated in this proposal have a direct use in highly secure quantum key distribution systems. Such systems may benefit ultra-secure applications in the military, government, and private sector. The sub-components developed have other applications in fields such as imaging, metrology, and quantum computation. For instance, we will be developing single photon detectors that operate at rates more than an order of magnitude higher than the current commercially available equivalents. Such detectors may be useful in a variety of applications including deep-space communications, optical instrumentation, laser ranging, and spectroscopy.


Grant
Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase I | Award Amount: 100.00K | Year: 2011

Detecting light at the single photon level is a fundamental measurement function that is useful in a wide variety of applications, including such diverse fields as biological spectroscopy, laser ranging, and quantum communications. Avalanche photodiode (APD) based single photon detectors (SPDs) are very convenient in that they are small solid state devices that don"t require cryogenic cooling. Si-based APD devices have high performance for<1 micron wavelengths. III-V material APDs are sensitive to the telecom bands (1.3 and 1.5 micron), but generally have inferior performance. Recently methods of high speed gating of III-V APDs has lead to dramatic improvements in their speed. We propose to optimize the III-V APD performance for high speed (GHz) gated operation by appropriate electronic control and system optimization. The use of nonlinear frequency conversion can allow for higher performance Si detectors to measure telecom wave-bands. The nonlinear interaction can add extra noise however. We will build a model for the noise processes and validate it with experimental measurements. The high speed performance of the Si detector will also be optimized. The feasibility of combining appropriate up-conversion with such high speed Si APDs for building low-noise multi-GHz detectors will be evaluated.


Grant
Agency: Department of Defense | Branch: Defense Advanced Research Projects Agency | Program: SBIR | Phase: Phase II | Award Amount: 750.00K | Year: 2010

Quantitative and visually intuitive information is critical to understanding, designing, and verifying the operation of any complex system. Measurement tools, such as vector signal analyzers which allow the visualization of radio frequency signal constellations, are now an indispensable part of modern engineering methods. There is intense interest in exploiting the special properties of quantum states for applications such as quantum communication and computing. However, the very properties of quantum states that make them useful also make them difficult to measure. Quantum state tomography is a measurement tool which allows for complete characterization of quantum states. Although great progress has been made in researching quantum tomography techniques, no commercial equipment exists and current demonstrations of the method tend to be slow, thereby providing little information about the quantum state drift over time. Advances in the field of quantum information are severely hampered because every development group must build their own tools including even basic measurement devices. It is the goal of this Phase-II SBIR to develop a real-time photonic quantum state tomography system. The prototype will measure both polarization-mode and time-mode signals at high speeds (~1s) and display the complex state information to the user in an intuitive way.


Grant
Agency: Department of Defense | Branch: Air Force | Program: STTR | Phase: Phase I | Award Amount: 99.99K | Year: 2010

Quantum key distribution (QKD) is an exciting application of the quantum theory to the important real-world problem of secure communications. Specifically, QKD may allow for provably secure key distribution. These random keys can then be used either in a one-time-pad style encryption system (for absolute security at low rates) or a standard encryption system (for high security at high rates). Traditional means of distributing keys are not provably secure. The value of QKD thus rests in its unprecedented high level of security, so it is critical to maintain the integrity of the theoretical security advantage in any actual implementation. In practice, issues associated with non-ideal components used in protocol implementation, and with information leakage from the classical communication channel required between the legitimate users, can make it more difficult to guarantee security. They also reduce the key rate and the maximum key distribution distance. We propose to investigate a new protocol for QKD that reduces the burden on the classical communication channel leading to better efficiency and more security. We also investigate the use of emerging technologies for quantum state generation and detection which may also improve efficiency, reach, and security of the QKD systems. BENEFIT: The technologies investigated in this proposal have a direct use in practical and highly secure quantum key distribution systems. Such systems may benefit ultra-secure applications in the military, government, and the private sector. The sub-components developed have other applications in fields such as imaging, metrology, and quantum computation. For instance, we will be developing very fast single-photon detectors. Such detectors may be useful in a variety of applications including deep-space communications, optical instrumentation, laser ranging, and spectroscopy.

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