Quantum communications

Multidimensional mode-separable frequency conversion for high-speed quantum communication

Quantum frequency conversion (QFC) of photonic signals preserves quantum information while simultaneously changing the signal wavelength. A common application of QFC is to translate the wavelength of a signal compatible with the current fiber-optic infrastructure to a shorter wavelength more compatible with high-quality single-photon detectors and optical memories. Recent work has investigated the use of QFC to manipulate and measure specific temporal modes (TMs) through tailoring the pump pulses. Such a scheme holds promise for multidimensional quantum state manipulation that is both low loss and re-programmable on a fast time scale. We demonstrate the first QFC temporal mode sorting system in a four-dimensional Hilbert space, achieving a conversion efficiency and mode separability as high as 92% and 0.84, respectively. A 20-GHz pulse train is projected onto 6 different TMs, including …


P Manurkar, N Jain, M Silver, YP Huang, C Langrock, MM Fejer, P Kumar, ...

Direct generation and detection of quantum correlated photons with 3.2 um wavelength spacing

Quantum correlated, highly non-degenerate photons can be used to synthesize disparate quantum nodes and link quantum processing over incompatible wavelengths, thereby constructing heterogeneous quantum systems for otherwise unattainable superior performance. Existing techniques for correlated photons have been concentrated in the visible and near-IR domains, with the photon pairs residing within one micron. Here, we demonstrate direct generation and detection of high-purity photon pairs at room temperature with 3.2 um wavelength spacing, one at 780 nm to match the rubidium D2 line, and the other at 3950 nm that falls in a transparent, low-scattering optical window for free space applications. The pairs are created via spontaneous parametric downconversion in a lithium niobate waveguide with specially designed geometry and periodic poling. The 780 nm photons are measured with a silicon …


YM Sua, H Fan, A Shahverdi, JY Chen, YP Huang

Interaction-free all-optical switching in χ(2)microdisks for quantum applications

We propose a quantum switch for telecom-band applications that is composed of a χ^(2) microdisk coupled to two fibers (or waveguides). The idea is to apply a pump pulse to shift the microdisk out of resonance, thereby switching the device between the cross and bar states in an interaction-free manner. As an example, a 2.5-μm-thick, 10μm radius GaAs microdisk with an intrinsic Q of ∼10^8 and a fiber-cavity-coupling Q of ∼10^4 can achieve low-loss (≲1%) switching for gigahertz-rate O-band quantum signals with milliwatt-peak-power pumps in the C band.


YP Huang, P Kumar

Programmable quantum random number generator without postprocessing

We demonstrate a viable source of unbiased quantum random numbers whose statistical properties can be arbitrarily programmed without the need for any postprocessing such as randomness distillation or distribution transformation. It is based on measuring the arrival time of single photons in shaped temporal modes that are tailored with an electro-optical modulator. We show that quantum random numbers can be created directly in customized probability distributions and pass all randomness tests of the NIST and Dieharder test suites without any randomness extraction. The min-entropies of such generated random numbers are measured close to the theoretical limits, indicating their near-ideal statistics and ultrahigh purity. Easy to implement and arbitrarily programmable, this technique can find versatile uses in a multitude of data analysis areas.


L Nguyen, P Rehain, YM Sua, YP Huang

Mode selective up-conversion detection with turbulence

We experimentally study a nonlinear optical approach to selective manipulation and detection of structured images mixed with turbulent noise. Unlike any existing adaptive-optics method by applying compensating modulation directly on the images, here we account for the turbulence indirectly, by modulating only the pump driving the nonlinear process but not the images themselves. This indirect approach eliminates any signal modulation loss or noise, while allowing more flexible and capable operations. Using specifically sum frequency generation in a lithium niobate crystal, we demonstrate selective upconversion of Laguerre-Gaussian spatial modes mixed with turbulent noise. The extinction reaches ~40 dB without turbulence, and maintains ~20 dB in the presence of strong turbulence. This technique could find utilities in classical and quantum communications, compressive imaging, pattern recognition, and so …


H Zhang, S Kumar, YP Huang

Chip-integrated device and methods for generating random numbers that is reconfigurable and provides genuineness verification

A device for generation of genuine random numbers, uses quantum stochastic processes in optical parametric nonlinear media. The dimensionality of the random numbers is varied from 2 to over 100,000. Their statistical properties, including the correlation function amongst random numbers, are tailored using linear and nonlinear optical circuits following the parametric nonlinear media. Both the generation and manipulation of random numbers are integrated on a single nanophotonics chip. By incorporating optoelectric effects, fast streams of random numbers are created in custom statistical properties, which are updated or reconfigured in real time, such as at 10 GHz speed. The unpredictability of the random numbers is quantifying by evaluating their min-entropy. The genuineness of quantum random numbers is tested using both statistical tools and independently verified by measuring the quantum entanglement …


Y Huang, YM Sua, J Chen, LTT Nguyen

Independent telecom-fiber sources of quantum indistinguishable single photons

Quantum-mechanically indistinguishable photons produced by independent (or equivalently, mutually phase incoherent) light sources are essential for distributed quantum information processing applications. We demonstrate heralded generation of such photons in two spatially separate telecom-fiber spools, each driven by pulsed pump waves that are measured to have no mutual phase coherence. Through Hong–Ou–Mandel experiments, we measure the quantum interference visibility of those photons to be 76.4±4.276.4\pm 4.2. Our experimental results are well predicted by a quantum multimode theory we developed for such systems without the need for any fitting parameter.


M Patel, JB Altepeter, YP Huang, NN Oza, P Kumar

Programmable Spatiotemporal Quantum Parametric Mode Sorter

We experimentally demonstrate a programmable parametric mode sorter of high-dimensional signals in a composite spatiotemporal Hilbert space through mode-selective quantum frequency up-conversion. As a concrete example and with quantum communication applications in mind, we consider the Laguerre-Gaussian and Hermite-Gaussian modes as the spatial and temporal state basis for the signals, respectively. By modulating the spatiotemporal profiles of the up-conversion pump, we demonstrate the faithful selection of signal photons in those modes and their superposition modes. Our results show an improvement in the quantum mode-sorting performance by coupling the up-converted light into a single-mode fiber and/or operating the up-conversion at the edge of phase matching. Optimizing pump temporal profiles allows us to achieve more than 12-dB extinction for mutually unbiased basis (MUB) sets of …


M Garikapati, S Kumar, H Zhang, YM Sua, YP Huang

Engineering fiber-nonlinearity based entangled photon sources for quantum key distribution applications

We model fiber parametric entangled photon sources for use in quantum key distribution applications. Effects of Raman scattered photons are evaluated and are found to be manageable when appropriately detuned optical filters are employed.


G Kanter, S Wang, YP Huang, P Kumar

Quantum Random Number Generator with Programmable Probability Distributions

We present a method of generating quantum random numbers with arbitrarily defined probability distributions featuring high dimensionality and post-processing free, for significantly improved Monte-Carlo simulations and data analyses.


L Nguyen, P Rehain, YM Sua, YP Huang

Frontiers in Optics, JTu3A. 30 1 2018

Devices and methods for giant single-photon nonlinearities

A periodically poled microring resonator structure, a method for fabrication of the periodically poled microring resonator structure, and a method to achieve giant single-photon nonlinearity are disclosed. The strong single-photon nonlinearity in the microring resonator structure is achieved through its optimized design and fabrication procedures.


Y Huang, J Chen

US Patent 11,754,908 2023

Systems and methods for quantum-secured, private-preserving computations

The present invention relates to methods for secure computation and/or communication. Entangled photons (118) are generated such that each participating party receives a series of optical pulses. Each party has private information (110, 112) which are never transmitted through public or private communication channels. Instead, each party converts their respective private information (110, 112) into measurement bases via an encryption process (114, 116) which are then applied to the entangled photons (118). After the measurement process, eg, quantum frequency conversion (122, 124), reference indices are announced (124, 126) so that computation can be performed (128) without revealing the private information directly or indirectly.


Y Huang, LTT Nguyen

US Patent 11,711,209 2023

Devices and methods for giant single-photon nonlinearities

A periodically poled microring resonator structure, a method for fabrication of the periodically poled microring resonator structure, and a method to achieve giant single-photon nonlinearity are disclosed. The strong single-photon nonlinearity in the microring resonator structure is achieved through its optimized design and fabrication procedures.


Y Huang, J Chen

US Patent App. 17/468,182 2022

A trustless decentralized protocol for distributed consensus of public quantum random numbers

Quantum random number (QRNG) beacons distinguish themselves from classical counterparts by providing intrinsic unpredictability originating from the fundamental laws of quantum mechanics. Most demonstrations have focused on certifiable randomness generators to guarantee the public that their genuineness is independent from imperfect implementations. These efforts however do not benefit applications where multiple distrusted users need a common set of random numbers, as they must rely on the honesty of beacon owners. In this paper, we formally introduce a design and proof-of-principle experiment of the first consensus protocol producing QRNs in a decentralized environment (dQRNG). Such protocol allows N number of participants contribute in the generation process and publicly verify numbers they collect. Security of the protocol is guaranteed given(N-1) dishonest participants. Our method is thus suited for distribute systems that requires a bias-resistant, highly secure, and public-verifiable random beacon.


L Nguyen, J Ramanathan, MM Wang, YM Sua, Y Huang

arXiv preprint arXiv:2108.12038 2021

Quantum systems for Monte Carlo methods and applications to fractional stochastic processes

Random numbers are a fundamental and useful resource in science and engineering with important applications in simulation, machine learning and cyber-security. Quantum systems can produce true random numbers because of the inherent randomness at the core of quantum mechanics. As a consequence, quantum random number generators are an efficient method to generate random numbers on a large scale. We study in this paper the applications of a viable source of unbiased quantum random numbers (QRNs) whose statistical properties can be arbitrarily programmed without the need for any post-processing and that pass all standard randomness tests of the NIST and Dieharder test suites without any randomness extraction. Our method is based on measuring the arrival time of single photons in shaped temporal modes that are tailored with an electro-optical modulator. The advantages of our QRNs are …


SF Tudor, R Chatterjee, L Nguyen, Y Huang

Physica A: Statistical Mechanics and its Applications 534, 121901 2019

Persistent Maritime Quantum Key Distribution

This report summarizes the findings of the whole project, whose purpose is to identify and develop suitable techniques for quantum secure communications over maritime environment. The focus is on overcoming the absorption, multi-scattering, turbulence, and background radiation that commonly exist in maritime atmospheres, To this end, this project executed experimental and theoretical research in the following three areas comparison analysis of wavelengths for maritime quantum communications using a laboratory testbed theoretical studies on entanglement transmission and optimal coding thereupon experimental demonstration of entanglement generation and detection in the optimized modes. This report provides technical details in those three research areas, which aggregately point to a viable wavelength channel for maritime quantum communications around 3.95 micron. Comparing with existing wavelength choices in the visible or near infrared spectra, this new wavelength offers unmatched advantages in overcoming multi-scattering, turbulence, and heat scintillation.


Y Huang, T Yu, R Martini, Stevens Institute of Technology


Weather-proof Quantum Communications

We identify a weather-proof channel for quantum communications using 3950 nm photons, and report on their generation and detection via parametric conversion with a measured coincidence to accidental ratio of 54±7 and spectral brightness of 4.4× 10 2 pair/s/nm/mW.


YM Sua, H Fan, A Shahverdi, JY Chen, R Martini, YP Huang

Frontiers in Optics, FM2D. 3 2017

Interaction-free All-optical Modulation on Chip

We report the observation of quantum Zeno blockade on chip, where a lightwave is modulated by another in a distinct “interaction-free” manner. For quantum applications, we also verify its operations on single photons.


JY Chen, YM Sua, ZT Zhao, M Li, YP Huang

Frontiers in Optics, JW4A. 12 2017

High-speed quantum communications in telecom fibers using overlapping temporal modes

We analyze an efficient quantum-communications architecture over telecom fibers using overlapping time-frequency modes and optimal receivers based on nonlinear processing.


VG Velev, J Larikova, P Kumar, YP Huang

Optical Fiber Communication Conference, W4F. 3 2015

Quantum interference of independently generated telecom-band single photons

We report on high-visibility quantum interference of independently generated telecom O-band (1310 nm) single photons using standard single-mode fibers. The experimental data are shown to agree well with the results of simulations using a comprehensive quantum multimode theory without the need for any fitting parameter.


M Patel, JB Altepeter, YP Huang, NN Oza, P Kumar

AIP Conference Proceedings 1633 (1), 249-251 2014

Quantum Communications with Overlapping Time Modes: Optimal Receiver Capable of Dispersion Compensation

We study fiber-transmission impairments of overlapping time-frequency modes for quantum communications in high-dimensional Hilbert space, and propose a class of optical receivers with built-in capability of overcoming such impairments.


J Larikova, VG Velev, P Kumar, YP Huang

Frontiers in Optics, FTu4A. 4 2014

Interaction-free All-optical Switches for Quantum Applications

We present a realization of all-optical switching in whispering-gallery-mode microcavities. Operating without the control and probe light beams overlapping in the cavity (in the asymptotic limit), such switches are ideal for use with quantum signals.


YP Huang, AS Kowligy, YZ Sun, DV Strekalov, P Kumar

Frontiers in Optics, FM4B. 2 2014

Long range quantum key distribution using frequency multiplexing in broadband solid state memories

We present simulations of rates for a quantum key distribution scheme using a frequency multiplexed repeater architecture with broadband solid-state quantum memories. We find that key can be generated over 1000 km with eight elementary links.


H Krovi, Z Dutton, S Guha, C Fuchs, W Tittel, C Simon, JA Slater, ...

CLEO: QELS_Fundamental Science, FTu1A. 5 2014

Secure Communication via Key Generation with Quantum Measurement Advantage in the Telecom Band

Our goal was to investigate the use of Keyed Communication in Quantum noise as a key generationdistribution mechanism with uThis report presents the development of an improved aerodynamic model of a flapping wing unmanned aerial vehicle FWUAV. Flapping wing flight is a complex phenomenon encompassing unsteady effects, controls using multiple degrees of freedom, creation of leading edge vortices, significant wing deformation, and extreme angles of attack during flight. These phenomena are not well modeled using the traditional conceptual aerodynamic models originally developed for fixed wing and rotary wing aircraft. In this study, Blade Element Theory is combined with momentum theory called Blade Element Momentum Theory BEMT to estimate aerodynamic loads on a FWUAV. The BEMT model is also combined with experimental scans of a FWUAV wing in a wind tunnel to represent the actual wing shape during flight represented by three-dimensional 3D scatter plots. These scatter plots are translated into spanwise-changing airfoil coordinates and used with thin airfoil theory to estimate the lift coefficient of the wing across the entire span at discrete points in the flap cycle. Finally, this lift coefficient estimation is used in conjunction with BEMT to create a comprehensive model for flapping wing flight and model calculations are compared against experimental data. se of a Coherent-state Pulse-Position Modulation protocol, including designing and constructing in the laboratory proof-of-concept experiments using off-the-shelf telecommunication components, as well as researching security analyses addressing a variety of attack …




Fiber-based multichannel correlated photon-pair source with high efficiency and low crosstalk

We present a fiber-based multichannel source of correlated photon pairs in the telecommunication O-band. Coincidence-to-accidental ratios> 100 (≃ 1) are measured between the paired (unpaired) signal-idler channels.


YZ Sun, YP Huang, NN Oza, P Kumar

CLEO: QELS_Fundamental Science, JTh2A. 89 2013

All-optical quantum switching

We will present progress in ultrafast all-optical quantum switching. c (3)-based devices can route entangled photons without disturbing their quantum state, whereas c (2)-based devices can, in principle, lead to dissipation-free quantum-optical Fredkin gates.


P Kumar, YP Huang

International Conference on Fibre Optics and Photonics, W1C. 1 2012

Ultrafast switching of photonic entanglement

We present our recent development of fiber-optic technology for all-optical switching and routing of entangled photons at high speeds, with minimal loss and added in-band noise, and-most importantly-without disturbing the photons' quantum state.


NN Oza, YP Huang, P Kumar

IEEE Photonics Conference 2012, 413-414 2012

Quantum information processing in the telecom waveband

We present recent progress in all-optical routing of entangled single photons at high speeds, with minimal loss and added in-band noise, and-most importantly-without disturbing the photons' quantum state.


P Kumar, YP Huang, JB Altepeter, M Patel, NN Oza, MA Hall

OFC/NFOEC, 1-3 2012

Addressing Security Issues in Quantum Key Distribution using Seed Keys and Entangled Sources

After years of analysis, security issues still remain in theory and practice of traditional quantum key distribution. A modified method offers alternate analysis paths and fewer hacking points. We consider entangled sources in this method.


GS Kanter, YP Huang, P Kumar

Applications of Lasers for Sensing and Free Space Communications, LTuA1 2011

Mixing light and matter waves: Principles and applications

The work of this dissertation is committed to theoretically explore rich physics involving quantum-mechanical mixing of light and matter waves, while specifically seeking applications in the fields of quantum interferometry, quantum information processing, and testing fundamental quantum mechanics. Towards this goal, the present research is guided by two lines. The first line is to study and manipulate collective behaviors of multi-atom systems at quantum-degenerate temperature, where the wave nature of atoms is maximized. Specifically, a variety of phase-coherent mixing processes of two macroscopic matter-waves, in the form of gaseous Bose-Einstein condensate (BEC), are investigated and engineered via (i) tuning atomic collisional interaction and/or inter-wave tunneling rate;(ii) mixing with optical waves of phase-locked lasers. By these means, a series of novel applications are proposed for generating highly …


Y Huang

Michigan State University 2009

Interaction-and measurement-free quantum information processing with single-atom and/or single-photon qubits

Interaction-free measurement (IFM) uses quantum interference to allow a single photon to detect a perfectly absorbing object without the photon interacting with the object directly. In high-efficiency IFM, the Quantum Zeno Effect is employed to increase the success probability from the original 50% to (Na)/N, where N is the number of cycles the photon makes through the device and a 1. In principle IFM protocols allow the hyperfine state of a single atom to become entangled with the polarization of a single photon. To date, attempts to employ this entanglement to create universal atom-atom quantum logic gates, such as CNOT gates, have not succeeded in achieving (Na)/N efficiency. In addition, they also require the detection of ancillary photons. At present, single-photon detection cannot be implemented experimentally with high efficiency. By making several key modications, we have developed a pair of …


M Moore, Y Huang

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 38 … 2007

Measuring an unknown phase with quantum-limited precision using nonlinear beamsplitters

High precision phase measurement is currently a central goal of quantum interferometry. In general, the precision is described by the phase estimation uncertainty δθ, which is characterized by two scaling behaviors, shot-noise limited with δθ∼ 1/√ N and Heisenberg limited with δθ∼ 1/N (N the total particle number). According to Bayesian analysis, Heisenberg limited preciosion for θ= 0 can be achieved in a Mach-Zehnder interferometer with (| N-1, N+ 1>+| N+ 1, N-1>)/√ 2 as input state based and a single measurement or| N, N> input based on multiple measurements. As θ deviates from zero, both schemes degrade rapidly to worse than shot-noise-limited precision. In contrast, a Quantum Fourier Transform (QFT) based interferometer can measure an arbitrary θ at Heisenberg limited precision, but requires a quantum computer. To extend the range of precisely measurable θ without a quantum computer, we …


Y Huang, M Moore

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 38 … 2007

Long-distance teleportation of atomic qubit via optical interferometry

The problem of long-distance teleportation of single-atom qubits via a common photonic channel is examined within the framework of a Mach-Zender optical interferometer. As expected, when a coherent state is used as input, a high-finesse optical cavity is required to overcome sensitivity to spontaneous emission. However, we find that a number-squeezed light field in a twin-Fock state can in principle create useful entanglement without cavity-enhancement. Both approaches require single photon counting detectors, and best results are obtained by combining cavity-feedback with twin-fock inputs. Such an approach may allow a fidelity of  using a two-photon input and currently available mirror and detector technology. In addition, the present approach can be conveniently extended to generate multi-site entanglement and entanglement swapping, both of which are necessities in quantum networks.


YP Huang, MG Moore

arXiv preprint quant-ph/0609214 2006