Date of Award
Electrical and Computer Engineering
Optical communications, Free space optical interconnects, Laser communication systems, Laser beams, Computer networks, optical, communication, communications, laser, power, beaming, wireless, transmission, high intensity, free space, VMJ, photovoltaic, vertical multi-junction
This research demonstrates the feasibility of utilizing high intensity laser power beaming (HILPB) systems as a conduit for robust free-space optical communications over large distances and in challenging atmospheric conditions. The uniqueness of vertical multi-junction (VMJ) photovoltaic cells used in HILPB systems in their ability to receive and to convert at high efficiency, very high intensity laser light of over 200 W/cm2, presents a unique opportunity for the development of the robust free space optical communication system by modulating information signals onto the transmitted high intensity photonic energy. Experiments were conducted to investigate and validate several optical communications concepts. A laser modulator was implemented to exhibit the excellent transient response of the VMJ technology at very high illumination intensities, and thus show its applicability to optical communications. In addition, beam polarization optic stages were employed to demonstrate a secure multi-channel communications scheme. The off-axis response of the receiver and the beam profile were characterized in order to evaluate the feasibility of developing acceptable pointing and tracking geometries. Finally, the impact of signal modulation on the total converted energy was evaluated and shown to have minimal effect on the overall power transmission efficiency. Other aspects of the proposed communication system are studied including: quantifying beamwidth and directivity, signal-to-noise-ratio, information bandwidth, privacy, modulation and detection schemes, transmission channel attenuation and disturbances (atmospheric turbulence, scintillation from index of refraction fluctuations, absorption and scattering from thermal and moisture variation) and beam acquisition tracking and pointing influence on the performance metrics of optical transmission technologies. The result of this research demonstrates the feasibility of, and serves as a comprehensive design guide for the implementation of a HILPB communication system. Su
Raible, Daniel Edward, "Free Space Optical Communications with High Intensity Laser Power Beaming" (2011). ETD Archive. 251.