Behzad Boroomandisorkhabi, a doctoral candidate in electrical engineering, will defend their dissertation titled “Optical Detection of Instantaneous Microwave Frequency and Displacement.” Their advisor, Dr. Mina Esmaeelpour, is an assistant professor in the electrical and computer engineering department. The dissertation abstract is provided below.

This dissertation explores developing and implementing novel photonic systems for instantaneous microwave frequency and displacement measurement, emphasizing cost-effectiveness, scalability, and high resolution. The research is encapsulated in three core studies: the design of all-fiber ultrafast ranging Lidar for medical motion management, the application of dispersive interferometry using picosecond laser pulses for laser ranging, and the integration of microwave photonic systems with digital signal processing (DSP) for enhanced measurement precision.
The work achieves micrometer scale displacement accuracy and microwave frequency resolutions within ±1 MHz across wide dynamic ranges by leveraging dispersive interferometry and time-stretch techniques. The studies underline the advantages of picosecond lasers as an alternative to femtosecond systems, providing practical solutions to mitigate challenges in cost, complexity, and environmental stability.

Key contributions include the development of dual Mach-Zehnder interferometers for bidirectional displacement detection and the integration of advanced DSP algorithms to optimize frequency extraction under noisy conditions. The innovations demonstrate applicability in diverse fields, including biomedical applications such as patient motion monitoring during procedures where conventional techniques are limited and real-time monitoring with high precision is required. Additionally, the developed techniques show potential in microwave frequency detection, offering enhanced precision and scalability for applications such as spectrum analysis and signal monitoring. These methods also contribute to precision metrology by providing accurate displacement and frequency measurements. Together, these advancements offer robust, compact, and scalable solutions for modern engineering challenges.

The findings significantly advance the field of photonic sensing and measurement, paving the way for broader applications of optical systems in industrial, medical, and scientific domains.