Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Free-space optical communication"”.
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Silicon Photomultipliers as Free Space Optical Communication Sensors
Free-space optical communications (FSOC) is a growing field that presents an attractive alternative to the the current technology standard of radio frequency (RF) communications. Typical optical carriers have smaller SWaP in comparison to RF systems due to the difference in required aperture sizes. …
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Low-Cost Spatial Light Modulator for Applications in Free-Space Optical Communication
… distortions. AO is an enabling technology for Free-Space Optical Communication, whose performance is severely degraded by the atmosphere. This thesis proposes two low-cost AO strategies: (1) repurposing Liquid Crystal (LC) SLM from an old display projector and (2) sensorless correction enabled …
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Laser beacon tracking for free-space optical communication on small-satellite platforms in low-earth orbit
Free-space optical (FSO) communication, or laser communication, is capable of providing high-rate communication links, meeting the growing downlink demand of space missions, including those on small-satellite platforms. FSO communication takes advantage of the high-gain nature of narrow laser beams …
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Reciprocity-enhanced time-division multiplexed optical switching with spatial diversity for free-space optical communication links
… analysis and experimental measurements of a free-space optical communications system that exploits optical reciprocity to switch between multiple (N) spatially-diverse apertures to increase data transmission through a scintillating channel. Electromagnetic signals, specifically optical, …
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Importance sampling simulation of free-space optical APD pulse position modulation receivers
Free-space optical communication technology has many advantages over RF/microwave in satellite and other spacecraft applications where reductions in size, weight and prime power requirements are combined with increased data transfer capability over long distances. Ultimately, the design and …
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Tracking algorithms under boundary layer effects for free-space optical communications
Free-space optical communication requires accurate tracking to maintain links. The tracking problem between an aircraft and satellite becomes more difficult with the introduction of a turret on the aircraft for increased field-of-regard. In the case of a hemispherical turret, the disrupted airflow …
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Experimental designs for efficient free-space multi-spatial-mode optical communication
In optical communications, two measures of efficiency are commonly at odds. The first is the photon information efficiency (in bits/photon) which measures the information that each detected photon conveys; the second is the spectral efficiency (in bits/s/Hz) which measures the bit rate achieved …
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100 Gbps ptical coherent modem for low earth orbit optical inter-satellite links
Free space optical communication (FSOC) provides a viable and cost-effective solution for future satellite systems with advantages in bandwidth, unregulated frequencies, and reduced system mass, volume, and power consumption in comparison with radio frequency systems. Several FSOC systems …
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Optical communication through the turbulent atmosphere with transmitter and receiver diversity, wavefront control, and coherent detection
Free space optical communication through the atmosphere has the potential to provide secure, low-cost, rapidly deployable, dynamic, data transmission at very high rates. However, the deleterious effects of turbulence can severely limit the utility of such a system, causing outages of up to 100 ms. …
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Superconducting nanowire single photon detectors for infrared communications
… approaching limits of classical physics. Quantum optical communications and information, based on single-photon detectors offer the most promising possibility to reach new levels of data rate and communication security. Superconducting nanowire single-photon detectors (SNSPDs) have already been …
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Dynamic pixel selection in free-space photon-counting optical communication systems for the exploitation of excess channel capacity
Atmospheric turbulence in free-space optical communications turns signal demodulation and decoding into a multimode problem as wavefronts of the transmitting laser beams are warped spatially past the desired form of a diffraction-limited spot at the receiver end of a free-space optical receiver. …
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Small satellite optical communication receiver for simultaneous spatial tracking and data demodulation
Free-space optical communications in space offer many benefits over established radio frequency based communication links; in particular, high beam directivity results in efficient power usage. Such a reduced power requirement is particularly appealing to small satellites with strict size, weight …
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Development of Optical Communication Terminals for Increasing Connectivity on Small Satellites
The development of free-space optical communication (FSOC) systems for space is key to enabling orders of magnitude more bandwidth and throughput for space communication systems. In addition, the recent developments in CubeSat technology can enable significant new small satellite capabilities. This …
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Strategies for limiting interference and interception of free space optical communications
Free space optical systems provide an attractive solution to communication needs that require inexpensive, easily deployable links capable of high data rate transmissions. A major challenge of free space optical communication is ensuring the integrity and confidentiality of the transmitted …
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The transistor-injected quantum cascade laser
… quantized states in the conduction band for optical emission. Due to the unipolar nature of the device, the quantum cascade laser cannot deliver spectrally stable output under different levels of current injection, which limits its application in gas sensing spectroscopy, imaging and free …
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Optical Communication Systems for Smart Dust
In this thesis, the optical communication systems for millimeter-scale sensing and communication devises known as "Smart Dust" are described and analyzed. A smart dust element is a self-contained sensing and communication system that can be combined into roughly a cubic-millimeter mote to perform …
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Optical communications for small satellites
… (LEO) is limited by the capabilities of the communications subsystem. Generally, these constraints stem from limited available electrical power, low-gain antennas and the general scarcity of available radio spectrum. In this thesis, we assess the ability of free space optical communication …
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Pointing system performance analysis for optical inter-satellite communication on CubeSats
Free-space optical communication using lasers (lasercom) is a leading contender for future space-based communication systems with potential advantages over radio frequency (RF) communication systems in size, weight, and power consumption (SWaP). Key benefits are due to the shorter wavelength: …
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Data-Driven Physical-Layer Optimization for RF and Optical Communications: Transmitarray Metasurfaces, Contextual-Bandit MUD, and Coherent Optical Links
… third carries the methodology onto a coherent optical link, where size, weight, and power constraints make a small-satellite deployment the natural target.</p> <p>The antenna work targets a tri-layer pixelated unit cell fabricated on Avient ABS550 by fused-deposition modeling, operated from 8 …