Eroded monomode optical fiber for whispering-gallery mode excitation in fused-silica microspheres

Abstract

We demonstrate the efficient excitation of high-Q whispering-gallery modes in near-spherical fused-silica microparticles in the size range 60-450 microm by the use of an eroded monomode optical fiber. When the sphere is placed in the evanescent field of the guided fiber mode, light is resonantly coupled from the fiber into the microparticle. We report a broadening of resonance modes and a shift of the resonance central frequency as the coupling strength is increased by reduction of the gap between the sphere and the fiber.

Enhanced coupling to microsphere resonances with optical fibers

“…11 The frequency shift and the linewidth broadening of the MDR's, which are both due to the OFC-microsphere interaction, were also studied. 12 However, in these OFC-microsphere experiments, the cladding of the fiber was not index matched to the media surrounding the microsphere, so there was an optical interface at the OFC surface. In this paper we report, for the first time to our knowledge, the excitation of the MDR's of a microsphere resting on the surface of an OFC whose surface has been wet with an index-matching oil to eliminate the air-fiber interface.…”

High-Q microsphere cavity for laser stabilization and optoelectronic microwave oscillator

“…Although proved to be most flexible and versatile, the prism coupler, is bulky and requires collimation and focusing optics to work with optical fiber. The previously reported attempts to directly couple a microsphere to an optical fiber had limited efficiency due to remaining phase mismatch (side-polished bent fiber coupler [23]), or still considerable size including few-cm core-to-cladding transformers (tapered monomode fiber coupler [24]). Here, we report a new and simple method of direct fiber coupling to high-Q WG modes in microsphere, which in essense is a hybrid of waveguide and prism coupler.…”

Optical Characterization of the Antigen-Antibody Thin Layer Using the Whispering Gallery Mode

“…[8][9][10][11] Some research groups have successfully excited the WGM in microspheres through the coupling of evanescent light. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] In particular, the attenuatedtotal-reflection (ATR) geometry has an advantage of an easy sample setting. Using the ATR configuration, we have already reported on the observation of resonance signals related to WGMs in microspheres with TiO2 thin film, and evaluated the optical properties of the film on the microsphere by using the WGM resonance.…”