Whispering gallery mode resonator has the characteristics of frequency selection, optical modulation and can greatly enhance the transmission density of the light in materials. It is widely used for wavelength selective absorption and optical interconnection modulator.
Figure 1. Physical map of optical path
Whispering gallery mode resonator with laser frequency selectivity is measured by OCI1500. It has a diameter of 1cm and is made of calcium fluoride. The light is transmitted as whispering gallery mode. During the measurement, a beam of light enters the T prism through a collimating mirror and is coupled into the whispering gallery mode resonator.
Figure 2. Schematic diagram of optical path
The positions of the end of emergence of collimating mirror, the end of incidence of T prism, and the end of emergence of T prim can be seen from the measurement results. The optical path surrounding the whispering gallery mode resonator is about 2cm and the total optical path is about 0.9m which is related to the Q value.
As the polarization state of light changes inside the whispering gallery mode resonator, the intensity of return loss at the contact surface of the T prism and the whispering gallery mode resonator exhibits periodic oscillation.
Figure 3. Measurement results