Research On The Whispering Gallery Mode Near The Fiber End Face

Microresonators of the optical whispering-gallery(WGM)modes have characteristic of high Q-factor and small sizes.The surface of an conventional optical fiber has been shown recently attractive qualities for long living whispering gallery modes that may propagate along the fiber surface.The propagate modes have a nonzero propagation velocity along the fiber axis,which depends on the effective radius variation of the optical fiber.Here show that such modes reflected by the optical fiber facet.Moreover,due to reflection,a locking effect occurs near the optical fiber facet for the whispering gallery modes with an axial component of the wave vector.Effective locking occurs due to the destructive interference of the waves coming from the excitation source and the waves reflected from the fiber facet.We derivate an analytical equation for determining the resonant wavelengths.We also experimentally measured the velocity of the optical pulse propagating in whispering gallery modes and reflecting from the fiber facet,its value is about 0.2 mm/ns.At the same time,by changing the effective radius near the fiber facet,we can control the propagation velocity of the optical pulse.The reflection effect of whispering gallery modes from the fiber facet has already shown intriguing potential applications in sensing,slowing light,filtering and switching.