Event
Ph.D. Research Proposal Exam: Charles J Turner
Friday, January 29, 2021
10:00 a.m.
Zoom Meeting https://umd.zoom.us/j/5461754790
Maria Hoo
301 405 3681
mch@umd.edu
ANNOUNCEMENT: Ph.D. Research Proposal Exam
Name: Steven Lipkowitz
Committee:
Dr. Thomas Murphy (Chair)
Dr. Thomas Antonsen
Dr. Yanne Chembo
Date/time: Friday, January 29, 2921 at 10:00am
Location: Zoom
Join Zoom Meeting
https://umd.zoom.us/j/5461754790
Title: Down-converting electro-optic mixer with Image rejection capability / Doubly-resonant dielectric-based electro-optic RF receiver in aluminum nitride
Microwave Photonics is the art of modulating an optical carrier with microwave or radio frequency (RF) signals, in order to take advantage of the benefits of photonic systems. In this way, microwave and RF signals can take advantage of the large instantaneous bandwidth, low loss transmission, and immunity to electromagnetic interference that are available to photonic systems and devices. Here I describe two microwave photonics experiments. The first is a system level experiment using commercial components, while in the second is a device level design.
First, I will discuss a microwave photonic down-converting mixer with image rejection capabilities. In this system level design, an incoming RF signal near 27 GHz is mixed with a local oscillator (LO) at 30 GHz to produce a 3 GHz intermediate frequency (IF) signal. This down-conversion allows for easier digitization and electrical signal processing once the signal is returned to the electrical domain via photo-detection. However, because the IF is determined to be the absolute difference between the RF and LO frequencies, an RF of 33 GHz will also be down-converted to 3 GHz. With this design, these two RF signals can be separated at the output of the system with a process known as image rejection.
Second, I will propose a device level design in which a bulk ceramic dielectric resonator is coupled to an optical resonator in aluminum nitride (AlN). In this design, the ceramic resonator behaves somewhat like an antenna, increasing the electric field strength in its immediate vicinity. By matching the free spectral range of the AlN optical resonator to the resonant frequency of the ceramic resonator, a significant increase in sensitivity to free-space radiation is expected. Additionally, while AlN is a weaker electro-optic material than the typical lithium niobate (LiNbO3), it is compatible with CMOS processing while LiNbO3 is not. This allows one to easily pattern the optical resonator into a shape that optimizes the RF to optical coupling. Finally, because there are no small conductive elements in the design, it is more resistant to electromagnetic attack than typical antenna-based systems.
