Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical and Computer Engineering, 2009. / Includes bibliographical references.

Thesis (Ph.D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves105-108)

The capacity of traditional wireless radio-frequency (RF) networks such as wireless fidelity (Wi-Fi) is insufficient to meet ever-increasing demand for bandwidth stemming from growth in smart, connected devices. The omni-directional nature of RF signals does not allow easy solutions that involve adding more access points to support more devices and capacity because they start to interfere with each other. Optical wireless communications (OWC) have already extended the superb bandwidth capacity of wired optical datalinks to sites that cannot be connected by traditional optical fibers, such as satellites and disaster recovery areas. Development of OWC technologies for dense, multi-user environments promises to bring these advantages to the home, office and other end-user environments. Optical spectral bands (0.1-10 micrometers) are suitable for directional antennas amenable to high spatial reuse and offer promising complementary wireless channels to help solve the spectrum crunch we are facing. Visible Light Communication (VLC), operating in the visible spectrum (0.4-0.7 micrometers) as a special case of OWC, offers great potential to increase Wi-Fi throughput as it can reuse dual-purpose solid-state light bulbs to provide optical datalinks in addition to lighting. The limited field-of-view of the receiver and the high probability of the mobile user blocking the receiver's active detection area are two significant impediments to the availability and communication range of line-of-sight links in VLC networks. We design and prototype a diversity combining VLC receiver with a multi-detector array, multistage amplifier, and Intensity Modulation-Direct Detection decoder capable of achieving highspeed data rates for white phosphorous LED light. We also design and prototype a multi-element, multi-datastream VLC transmitter for providing mobile data connectivity in dense VLC networks, using imaging-based beam-steering to enable dense deployment. Finally, we investigate OWC receiver design and channel behavior in photon-starving environments such as water-to-air links.

Optical communication systems had successfully met the increasing demands for higher communication speeds through the utilization of all degrees of freedom of the light propagating in a single-mode fiber (SMF). However, the Shannon limit restricts further improvements of the capacity in the SMFs. Space-division multiplexing (SDM) offers a way for further increasing the capacity of optical fibers through the utilization of the spatial domain. However, for it to be successfully implemented, many integral parts of the optical communication must be tuned or modified to work effectively with the multimode fibers, including few-mode amplifiers, and mode converters. In this work, we first develop the few-mode semiconductor optical amplifier (FMSOA) that provides an equalized-gain for E11, E12, E21, and E22 modes. The fabricated InGaAsP MQW FMSOA shows that the modes are confined to the ridge waveguide, overlapping the quantum wells with approximately the same amount, leading to equalized gain for each of the four waveguide modes. Second, we develop an all-optical mode and wavelength converter (AOMWC) using the inter-modal four-wave mixing (FWM) process in an FMSOA. At the nonlinear regime of an FMSOA, the interaction of waves with different wavelengths and modes creates gain and index gratings. These gratings provide a very efficient inter-modal FWM process. The high mode selectivity and the efficient FWM make the FMSOA an appealing AOMWC for integrated all-optical signal processors. Lastly, an asymmetric supermode converter is demonstrated by encircling the exceptional point in a non-Hermitian system. Encircling the exceptional point leads to a direction-dependent coalesce of the eigenvalues and merge of the eigenvectors. The supermode converter is designed by manipulating the gain and the propagation constant along the length of a directional coupler. Independent of the input, the output of the coupler merge to a unique single eigenstate at each end of the coupler.

No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 247-259). Also available on the Internet.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 159-167).

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 247-259). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 118-130).

Thesis (M.A.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 103-105).