Proceedings Article | 7 February 2012
Proc. SPIE. 8236, Laser Resonators, Microresonators, and Beam Control XIV
KEYWORDS: Modulators, Modulation, Microwave radiation, Receivers, Microwave photonics, Electro optics, Photonic microstructures, Electrooptic modulators, Resonators, Oscillators
The quest for low power and high frequency electro-optical modulator has been one of the important endeavors in
microwave photonics. The advent of microdisk electro-optic modulator created a new domain in optical modulator and
photonic microwave receiver design by exploiting the unique properties of high quality (high-Q) Whispering-Gallery
Mode (WGM) optical cavities. High-Q crystalline WG cavities were the first devices used as compact and low power
resonant electro-optical modulators and gradually semiconductor and polymer based microdisk and microring
modulators emerged from this core technology. Due to its small size, high sensitivity and limited bandwidth, originally
microdisk modulator was developed with the objective of replacing the conventional microwave wireless receiver frontend
with a sensitive photonic front-end. Later it was shown that the electro-optic microdisk modulator could also
function as a microwave frequency mixer in optical domain. Starting from fundamentals of resonant electro-optic
modulation in high-Q WGM cavities, in this paper we review the development of high sensitivity microdisk modulators
and the recent progress toward more efficient modulation at higher frequencies. Next related topics such as singlesideband
modulation, all-dielectric photonic receiver, and semiconductor microring modulators are briefly discussed.
Finally, photonic microwave receiver configurations that employ high-Q optical resonance for modulation, filtering and
mixing are presented. We will show that high-Q optical resonance is one of the promising routes toward the general idea
of an all-optical microwave receiver free of high frequency electronic transistors, mixers and filters.
