Analytical model for coupling Whispering gallery mode silica microcavity for sensing application

摘要

An analytical expression for the coupling of whispering gallery mode is derived by adding the coupling and intrinsic loss terms. The resonant frequency of a weak probe mode can be shifted by a strong pump mode due to XPM and the frequency shift of the probe is proportional to the pump energy. We found large negative frequency shift when pump and probe power are perfectly matched, consistant with the reported experimental observations. It can also be found that XPM induced frequency shift is much smaller as compared with SPM induced frequency shift due to the lower power coupled to mode 2. This result opens up a range of new applications in nonlinear sensing and quantum optics.