Date of Award
Master of Science
Department of Electrical and Computer Engineering
James A. Lott, PhD
Tunable micro-optical devices are expected to be vital for future military optical communication systems. In this research I seek to optimize the design of a microelectromechanical (MEM) structure integrated with a III-V semiconductor micro-optical device. The resonant frequency of an integrated optical device, consisting of a Fabry-Perot etalon or vertical cavity surface emitting laser (VCSEL), may be tuned by applying an actuation voltage to the MEM Flexure, thereby altering the device's optical cavity length. From my analysis I demonstrate tunable devices compatible with conventional silicon 5V integrated circuit technology. My design for a Fabry-Perot etalon has a theoretical tuning range of 200 nm, and my VCSEL design has a tuning range of 44nm, both achieved with actuation voltages as low as 4V. Utilizing my theoretical device designs I planned a new microelectronics fabrication process to realize a set of prototype MEM-tunable devices with a peak central emission wavelength at 980nm. I designed a mask set consisting of 8 mask levels and 252 distinct device designs, all within a die size of one square centimeter. My unique fabrication process utilizes a gold MEM flexure with a Si3N4/SiO2 dielectric distributed Bragg reflector (DBR) mirror, grown on an all-semiconductor VCSEL or Fabry-Perot substrate. I successfully fabricated a complete set of MEM-tunable test structures using the cleanroom laboratory facilities at the Air Force Institute of Technology (AFIT) and the Air Force Research Laboratory (AFRL). The initial devices display minimum electrostatic actuation voltages as low as 1.8 V, which is comparable to existing MEM tunable VCSEL designs. In order to enhance device performance, I developed improvements to my laboratory process for incorporation in future fabrication runs. These results form the fundamental basis for advanced development of manufacturable MEM-tunable optical emitting and detecting device arrays.
DTIC Accession Number
Harvey, Michael C., "Design and Fabrication of Micro-Electro-Mechanical Structures for Tunable Micro-Optical Devices" (2002). Theses and Dissertations. 4368.