Computer-generated holograms for free-space optical interconnects

Abstract

This dissertation describes an investigation into the use of computer generated holograms to implement free-space optical interconnects. Computer generated holograms are discussed in terms of their theory of operation, design principles, fabrication techniques, optical performance, and sources of error. To motivate the research, discussion of an optoelectronic computing module is included; the device uses computer generated holograms to implement large-fanout optical interconnects. The emphasis of this dissertation is not on a specific application, rather it is focused on understanding the abilities and limitations of computer generated holograms. New contributions are made in the area of hologram design, both individual and multifaceted elements. These design techniques were built into a computer aided design tool (SPIDER 3.0), which was developed to promote the use of computer generated holograms. Hologram fabrication techniques and optical performance are also carefully characterized. Measurements show that performance is poorer than what is expected. Several significant sources of error are identified in the design and fabrication of computer generated holograms, and these effects are shown to explain most of the measured results. The dissertation concludes that computer generated holograms are currently limited by errors in fabrication and in the approximate diffraction theories employed in the design process. While the optical performance of the holograms is not as good as expected, the results are shown to be adequate for successful use in real applications.