Wavefront sensing for terrestrial, underwater, and space-borne free-space optical communications

Gładysz, Szymon; Zepp, Andreas; Segel, Max; McDonald, Douglas; Bellossi, Raphael; Lechner, Daniël; Gasperin, Osvaldo Javier Galicia; Stein, Karin

doi:10.1117/12.2595727

Cited by 5 publications

(5 citation statements)

References 15 publications

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“…Furthermore, when it is considered that receiver apertures are parameterized with a finite length and power averaging needs to be considered, the power scintillation index σ 2 p is introduced. Its final equation is given in (9), where parameter d is calculated based in (10) [27].…”

Section: Atmospheric Turbulence Attenuation Based On Raob Databasementioning

confidence: 99%

“…In order to compensate for the phase distortion, the reconstruction process is based on a deformable mirror controlled by a wave-front sensor. While the use of Shack-Hartmann wave sensor prevails within the last decade, its bandwidth limitations and saturation losses lead to the development of other early-stage technologies such as modal holographic wave-front sensors based on the Karhunen-Loève modes [9]. In addition, digital adaptive optics for turbulence mitigation is also considered [10].…”

Section: Introductionmentioning

confidence: 99%

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Testbed Emulator of Satellite-to-Ground FSO Downlink Affected by Atmospheric Seeing Including Scintillations and Clouds

et al. 2022

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Free Space Optics (FSO) technology enabling next-generation near-Earth communication is prone to severe propagation losses due to atmospheric-turbulence-induced fading and Mie scattering (clouds). As an alternative to the real-time evaluation of the weather effects over optical signal, a state-of-the-art laboratory testbed for verification of slant APD-based (Avalanche Photodiode) FSO links in laboratory conditions is proposed. In particular, a hardware channel emulator representing an FSO channel by means of fiber-coupled Variable Optical Attenuator (VOA) controlled by driver board and software is utilized. While atmospheric scintillation data are generated based on Radiosonde Observation (RAOB) databases combined with a statistical design approach, cloud attenuation is introduced using Mie theory together with empirical Log-Normal modeling. The estimation of atmospheric-turbulence-induced losses within the emulated optical downlink is done with an FSO IM/DD prototype (Intensity Modulation/Direct Detection) relying on two different data throughputs using a transmitter with external and internal modulation. Moreover, the receiver under-test is a high-speed 10 Gbps APD photodetector with integrated Transimpedance Amplifier (TIA) typically installed in OGSs (Optical Ground Stations) for LEO/GEO satellite communication. The overall testbed performance is addressed by a BER tester and a digital oscilloscope, providing BER graphs and eye diagrams that prove the applied approach for testing APD-TIA in the presence of weather-based disruptions. Furthermore, the testbed benefits from the used beam camera that measures the quality of the generated FSO beam.

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Section: Atmospheric Turbulence Attenuation Based On Raob Databasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Testbed Emulator of Satellite-to-Ground FSO Downlink Affected by Atmospheric Seeing Including Scintillations and Clouds

et al. 2022

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“…More recent wavefront sensor developments include holographic and sensor-less techniques. 7 These systems compensate for turbulence in real time and use the full optical bandwidth of the receiving telescope. However, such systems still rely on reference source beacons in conjunction with deformable mirrors to physically apply the compensations and are thus generally expensive and complicated to operate.…”

Section: Introductionmentioning

confidence: 99%

“…A common AO method leverages a Shack–Hartmann 6 wavefront sensor; this device uses a microlens array to estimate phase aberrations. More recent wavefront sensor developments include holographic and sensor-less techniques 7 . These systems compensate for turbulence in real time and use the full optical bandwidth of the receiving telescope.…”

Section: Introductionmentioning

confidence: 99%

Digital adaptive optics with interferometric homodyne encoding for mitigating atmospheric turbulence

et al. 2023

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Digital adaptive optics (DAO) created using homodyne encoding can mitigate atmospheric turbulence in passive imaging systems. This work demonstrates a self-referencing homodyne interferometry technique that combines the passive imaging utility of multiframe algorithmic procedures with the single-frame correction capability of the Shack-Hartmann adaptive optics technique. This paper presents image reconstruction improvements through the addition of (1) phase diversity modulation techniques within the interferometry reconstruction algorithm and (2) temporal image processing techniques applied after the interferometry reconstruction algorithm. By imaging quick response codes through a turbulent air chamber in the laboratory, it was possible to quantify the machine-readable performance gain provided by DAO when compared with a standard imaging camera. Results from this research verify that DAO from homodyne encoding provides turbulence mitigation for single frames of data, paving the way for environmentally robust, high-speed, self-contained imaging systems.

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“…The most common wavefront sensor is a Shack-Hartmann 6 wavefront sensor, that utilizes a micro-lens array. More recent wavefront sensor developments include holography and sensor-less techniques 13 . These techniques still rely on using LASERS or some type of beacon as a reference source in conjunction with a deformable mirror to physically apply the compensation.…”

Section: Introductionmentioning

confidence: 99%

Digital adaptive optics with interferometric homodyne encoding for mitigating atmospheric turbulence for imaging applications

Drexler¹,

Lilledahl²,

Laxton³

et al. 2023

Computational Imaging VII

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Digital Adaptive Optics created using homodyne encoding can mitigate atmospheric turbulence in passive imaging systems. This work demonstrates a self-referencing homodyne interferometry technique that combines the passive imaging utility of multi-frame algorithmic procedures with the single-frame correction capability of the Shack-Hartmann adaptive optics technique. As an expansion of recent progress on 3 sub-aperture assemblies, this work showcases the latest results from the NIWC Pacific team to include coherently reconstructing 18 sub-apertures.

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Wavefront sensing for terrestrial, underwater, and space-borne free-space optical communications

Cited by 5 publications

References 15 publications

Testbed Emulator of Satellite-to-Ground FSO Downlink Affected by Atmospheric Seeing Including Scintillations and Clouds

Testbed Emulator of Satellite-to-Ground FSO Downlink Affected by Atmospheric Seeing Including Scintillations and Clouds

Digital adaptive optics with interferometric homodyne encoding for mitigating atmospheric turbulence

Digital adaptive optics with interferometric homodyne encoding for mitigating atmospheric turbulence for imaging applications

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