Dr. Yousef K. Chahine Profile

Dr. Yousef K. Chahine

at NASA Glenn Research Ctr

SPIE Involvement:

Author

Publications (11)

Proceedings Article | 3 October 2024 Presentation + Paper

Coherent mode decomposition of Kolmogorov optical turbulence in a finite aperture

Yousef Chahine

Proceedings Volume 13147, 1314706 (2024) https://doi.org/10.1117/12.3028094

KEYWORDS: Turbulence, Optical coherence, Optical turbulence, Modal decomposition, Physical coherence, Partial coherence, Atmospheric propagation, Atmospheric optics, Covariance, Quantum numbers

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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 | 12 March 2024 Presentation + Paper

Performance of a real-time photon counting optical receiver in the presence of emulated channel fading

Jennifer Downey, Yousef Chahine, Sarah Tedder, Evan Katz, Michael Marsden, John Clapham

Proceedings Volume 12877, 128770Z (2024) https://doi.org/10.1117/12.3002472

KEYWORDS: Receivers, Field programmable gate arrays, Detector arrays, Turbulence, Telecommunications, Beam divergence, Transmitters

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Free-space optical communication links with terrestrial ground stations experience fading due to atmospheric scintillation and beam pointing. Fiber-coupled receiver systems experience additional fading at the interface between the fiber and free-space optics of the telescope. The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has characterized a real-time photon-counting optical ground receiver system with an atmospheric fade emulation system. The receiver system is comprised of a fiber interconnect, an array of Superconducting Nanowire Single Photon Detectors (SNSPDs), and a Field Programmable Gate Array (FPGA) based receive modem. Two fiber interconnect/detector architectures have been studied. One architecture uses a 70-mode photonic lantern coupled to seven single pixel SNSPDs. The other architecture uses a 10-mode Few-Mode Fiber (FMF) coupled to a 15-pixel SNSPD array. The receiver system complies with the Consultative Committee for Space Data Systems (CCSDS) optical communications high photon efficiency coding and synchronization standard, which uses Serially Concatenated convolutionally coded Pulse-Position Modulation (SCPPM). The CCSDS standard is designed for use in low photon flux missions, including the Orion Artemis-II Optical (O2O) communications demonstration. The standard utilizes a convolutional symbol interleaver which can be resized to mitigate different fades. The fade emulation system employed in this work emulates scintillation-induced, pointing-induced, and coupling-induced fading. This paper gives an overview of the real-time optical receiver system and the fade emulation system. It presents tests results which show the impact of fading on the performance on the receiver. The test results show that in the presence of channel fading, the 70-mode photonic lantern outperforms the 10-mode FMF under higher (𝐷/𝑟₀ = 9) turbulence conditions due to high fiber-coupling-induced fading and fiber coupling loss on the 10-mode FMF. When operating in lower turbulence (𝐷/𝑟₀ = 4), the 10-mode FMF outperforms the 70-mode photonic lantern. The paper also shows a larger convolutional interleaver improves the system performance as long as the receiver does not lose acquisition.

Proceedings Article | 15 March 2023 Poster + Paper

Statistical analysis of fading power vectors for real-time atmospheric channel emulation

Yousef Chahine, Evan Katz, Brian Vyhnalek, Sarah Tedder

Proceedings Volume 12413, 124131L (2023) https://doi.org/10.1117/12.2648447

KEYWORDS: Scintillation, Optical fibers, Free space optical communications, Receivers, Analytic models, Turbulence, Statistical modeling, Monte Carlo methods, Single mode fibers, Linear filtering, Statistical analysis

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Proceedings Article | 15 March 2023 Poster + Paper

Folded optical design for high fidelity atmospheric emulation with a spatial light modulator

Sarah Tedder, Yousef Chahine

Proceedings Volume 12413, 124131I (2023) https://doi.org/10.1117/12.2646884

KEYWORDS: Spatial light modulators, Reflection, Holograms, Optical design, Atmospheric optics, Wavefront sensors, Design and modelling, Atmospheric propagation

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Proceedings Article | 4 March 2022 Presentation + Paper

Numerical phase space optics methods and applications to the analysis of fiber coupling efficiency in atmospheric turbulence

Yousef Chahine, Ferrill Rushton, Brian Vyhnalek, Sarah Tedder

Proceedings Volume 11993, 119930U (2022) https://doi.org/10.1117/12.2607513

KEYWORDS: Waveguides, Photonics, Atmospheric optics, Atmospheric propagation, Step index fibers, Graded index fibers, Geometrical optics, Fiber couplers, Turbulence, Wigner distribution functions, Optical phase space, Free space optical communications

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Proceedings Article | 4 March 2022 Presentation + Paper

Insertion loss of a multi-plane light conversion device with few mode fiber outputs under atmospheric conditions

Sarah Tedder, Brian Vyhnalek, Yousef Chahine, Bertram Floyd

Proceedings Volume 11993, 1199305 (2022) https://doi.org/10.1117/12.2607306

KEYWORDS: Turbulence, Spatial light modulators, Receivers, Holograms, Telescopes, Single photon detectors, Single mode fibers

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SPIE Journal Paper | 30 March 2021

Laser beam propagation simulations of long-path scintillation and fade with comparison to ground-to-aircraft optical link measurements

Yousef Chahine, Adam Wroblewski, John Malowicki, Joseph Flatico, Gunnar Ristroph, Alex Hsia, Rani Megally, Adam Resnick

OE, Vol. 60, Issue 03, 036112, (March 2021) https://doi.org/10.1117/12.10.1117/1.OE.60.3.036112

KEYWORDS: Scintillation, Optical simulations, Atmospheric propagation, Atmospheric optics, Atmospheric modeling, Laser beam propagation, Turbulence, Computer simulations, Wave propagation, Optical engineering

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Proceedings Article | 2 March 2020 Presentation + Paper

Measurements of few-mode fiber photonic lanterns in emulated atmospheric conditions for a low earth orbit space to ground optical communication receiver application

Sarah Tedder, Bertram Floyd, Yousef Chahine, Benjamin Croop, Brian Vyhnalek, Christopher Betters, Sergio Leon-Saval

Proceedings Volume 11272, 112720U (2020) https://doi.org/10.1117/12.2542848

KEYWORDS: Single mode fibers, Atmospheric propagation, Sensors, Receivers, Turbulence, Atmospheric modeling, Atmospheric optics, Telescopes, Earth's atmosphere

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Proceedings Article | 2 March 2020 Paper

Acousto-optic modulator for emulating atmospheric fade in free-space optical communication systems

Evan Katz, Yousef Chahine, Brian Vyhnalek, Sarah Tedder

Proceedings Volume 11272, 1127219 (2020) https://doi.org/10.1117/12.2546511

KEYWORDS: Atmospheric optics, Optical simulations, Receivers, Atmospheric modeling, Telecommunications, Turbulence, Atmospheric propagation, Signal attenuation

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Proceedings Article | 2 March 2020 Paper

Beam propagation through atmospheric turbulence using an altitude-dependent structure profile with non-uniformly distributed phase screens

Yousef Chahine, Sarah Tedder, Brian Vyhnalek, Adam Wroblewski

Proceedings Volume 11272, 1127215 (2020) https://doi.org/10.1117/12.2543583

KEYWORDS: Turbulence, Atmospheric propagation, Scintillation, Atmospheric optics, Wave propagation, Beam propagation method

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Showing 5 of 11 publications

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