An optical microresonator includes microcylinder and spiral resonant
waveguide formed on the microcylinder that optically couples light from
an optical source waveguide to the microcylinder and slows light
propagating along the microcylinder. A coupling element, for example, a
diffraction grating can be operative with the resonant waveguide
structure and configured to meet a desired phase matching. A second
microcylinder having a spiral resonant waveguide formed thereon can be
positioned adjacent to the spiral resonant waveguide formed on the first
microcylinder for coupling therewith. The spiral resonant waveguides on
first and second microcylinders can be configured for slowing light
propagating along the microcylinder.