Waveguide-coupled octagonal microdisk channel add-drop filters.
We report planar waveguide-coupled octagonal microdisk channel add-drop filters on silicon nitride-on-silica substrates. Using ray optics, we show that discrete octagonal cavities have wave-front-matched four- and eight-bounce ray orbits. From a planar waveguide-coupled 50-microm-sized octagonal microdisk filter, our experiment demonstrates TM-polarized eight-bounce modes with a coupling efficiency of approximately 56%, Q approximately equal to 1150, and a finesse of approximately 5. Using the two-dimensional finite-difference time-domain method, we obtain qualitative agreement between measurement and simulation of a smaller-sized waveguide-coupled octagonal microdisk filter.
Department of Electrical and Electronic Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Chao
C
Li
Ning
N
Ma
Andrew W
AW
Poon