WGM-FP hybrid droplet-like microbubble resonator and application to all-optical tuning

In this work, we present for the first time, to the best of our knowledge, a whispering gallery mode (WGM)-Fabry-Perot (FP) mixed-mode droplet-like microbubble resonator with a unique configuration that allows it to have both WGMs and FP resonances. We experimentally demonstrate its outstanding advantages in the field of all-optical tunability by increasing the control light power to bring its whispering gallery mode resonance wavelength tuning range to an astonishing 8.77 nm with a tuning sensitivity of 33.24 pm/mW. For FP interference, the tuning sensitivity reaches 62.84 pm/mW. This hybrid resonator is expected to be used in tunable lasers, filters, etc. The ability to excite multiple resonant modes at the same time is also extremely suitable for multi-parametric sensing.