Abstract

Ultra-high-Q silica microspheres have attracted interest as potential narrow bandwidth filters, compact laser sources¹ and for fundamental studies in quantum and nonlinear optics.² In these applications, precise knowledge of the modal characteristics is often required. Ideally, microspheres are true traveling-wave-resonators, where it is possible to excite either the clockwise or counterclockwise mode. However, small amounts of intrinsic scattering in the resonator can lead to power backscattering into the oppositely-oriented mode. This coupling lifts the normally degenerate CW and CCW modes, resulting in a doublet structure (Figure 1).³

© 2002 Optical Society of America