not mine. can get the file from https://slideplayer.com/slide/14555860/

1. Micro-ring resonators
in mid-IR
Junchao Zhou
PHYS 689

2. Review of some basic concepts of micro-ring resonators
Coupling Region
1
𝛼: Loss coefficient of the ring; 𝜃 = 𝜔𝐿/𝑐
1. Gap distance
2. Coupling length
3. Refractive index

3. On resonance:
Critical coupling when 𝛼=|t|, 𝑃𝑡1 = 0

4. Ring resonators parameters:
𝑟 = 148𝜇𝑚
FSR
FWHM Finess:
Quality factor:

5. Several configurations:

6. Micro-ring resonators in mid-IR
Application
• Wavelength filter for sensors, biomedical sensing
• Optical communication
Common materials for mid-IR waveguides
• Si
• Ge
• Si3N4
• AlN
• Al2O3
• Chalcogenide

9. On resonance:

10. r1 = 100 µm
r2 = 110 µm
r1 = 100 µm
r2 = 102.5 µm

12. Device fabrication: