Photonic Processing of Ultra-broadband Radio Frequency Waveforms

Ehsan Hamidi
Purdue University

Monday, May 24, 2010 at 4:00pm
Engr IV Maxwell Room 57-124

Abstract
Photonic processing has been becoming an appealing alternative to process ultra-broadband electrical signals with bandwidths in excess of multi GHz with almost two hundred percent fractional bandwidth. Moreover it benefits from properties such as large bandwidth, immunity to electromagnetic interference, tunability, and programmability compared to electrical processing. Therefore microwave photonic techniques can be utilized to enhance the performance of analog radio frequency systems in detection and filtering of ultra-broadband waveforms.

In this talk, the first implementation of microwave photonic matched filters based on hyperfine optical pulse shaping to compress ultra-broadband arbitrary radio frequency waveforms will be presented. These filters which have arbitrary frequency responses enable real-time fast processing of ultra-broadband signals. Further more the application of this technique to post-compensate broadband antenna's dispersion will be discussed. Finally for the first time tunable programmable microwave photonic filters based on optical frequency combs will be presented. These filters have finite impulse responses where the tap weights can be programmed by arbitrary complex coefficients. The large number of comb lines provides more freedom to shape the filter bandpass resulting in highly selective filters while achieving tunability using a simple scheme.

Biography
Ehsan Hamidi received the B.S. degree in Electrical Engineering from Sharif University of Technology, Tehran, Iran, in 2005, and is currently a Ph.D. candidate in the School of Electrical and Computer Engineering at Purdue University, West Lafayette, IN. He has been a Research Assistant in the Ultrafast Optics and Optical Fiber Communication Laboratory since 2005. His current research interests include Radio Frequency Photonics, Ultrafast Optics, Optical Pulse Shaping, and Optical Signal Processing, Optical Frequency Combs, and Optical Metrology. Mr. Hamidi is a student member of the IEEE Lasers and Electro-Optics Society and the IEEE Communication Society. He was nominated as a student paper award finalist in 29th URSI General Assembly and 2009 IEEE International Symposium on Antennas and Propagation. He has served as a reviewer for IEEE/OSA Journal of Lightwave Technology, IEEE Photonics Technology Letters, and Optics Letters.