| Cylindrical lithography is the methodology used for designing and fabricating active and passive structures on cylindrical surfaces. Substrates of interest include optical fibers, capillary tubes, catheters, piezoelectric rods, and others. This dissertation describes work which expanded the abilities of cylindrical microfabrication by increasing the number and types of materials that have been successfully deposited on cylindrical substrates, increasing the complexity of the substrate itself, developing postdeposition processing methods for curved surfaces, and applying these new abilities to the fabrication of an optical fiber modulator element consisting of a piezoelectric thin film surrounding an embedded optical fiber Bragg grating.; The processing methods devised were applied successfully individually. The piezoelectric material used, PZT, was deposited on an optical fiber substrate using RF magnetron sputtering methods, to a thickness of around 5{dollar}mu{dollar}m. Postdeposition processing methods including PZT annealing and poling were performed. Rapid thermal annealing methods using a carbon dioxide laser system was investigated. Annealed films showed successful conversion from amorphous to perovskite phases, using XRD analysis. Conventional annealing methods were also used. Problems were encountered which affected fiber substrate mechanical properties, probably due to the propagation of micro-surface flaws during the annealing process. PZT and platinum thin films were also adversely affected during post deposition processing. A fiber modulating device was finally constructed using a thin and small diameter extruded PZT tube, but with sub-optimal performance.; Cylindrical lithography was further developed by investigating the use of capillary tubes, with thin films of chrome on the outside surface, as lithography photomasks. Patterns were written on the outside surface using e-beam lithography techniques. Patterns consisting of lines going longitudinally down the tube, and rings going circumferentially around the tube, were drawn on the masks and successfully transferred to cylindrical substrates. A model was devised which analyzed diffraction effects through capillaries, including the effects of refraction and spreading by curved interfaces. The model predicted resolution limits of 7-14{dollar}mu{dollar}m for the mask and substrate dimensions used. The model was verified by experimental data with fairly good agreement.; Practical considerations for the use of capillary masks are discussed, including the need to use index matching fluid to fill the space between the capillary mask and substrate. Finally, the advantages and disadvantages of this method are mentioned, and suggestions are made as to the direction of future research. |
