Study of whispering gallery modes in a cylindrical microresonator excited by a tilted fiber taper

摘要

We studied the excitation of whispering gallery modes (WGMs) in a cylindrical microresonator formed by a short length of a multimode fiber. The light was evanescently coupled into the fiber from a micro-cylinder whose tilt angle was varied from perpendicular to parallel with respect to the fiber taper. Narrow WGM resonances are observed in the transmission spectrum of the fiber taper with a maximum Q factor of ～10~5. Evolution of the transmission spectrum with the change of tilt angle involved changes in the number of WGMs in the spectrum for smaller tilts and the disappearance of WGM resonances at large tilt angles.