title: Second-order filtering and sensing with partially coupled traveling waves in a single resonator.
abstract: The counterpropagating waves in a single traveling-wave cavity can be partially coupled by means of a small perturbation such as a notch. When it is side coupled to a waveguide, this single cavity yields a general second-order (Chebyshev) reflection response in the waveguide, which is useful for narrow-bandwidth reflecting applications. In a different application, the cavity amplifies small reflections induced by external perturbations, thus finding use in ultrafine sensing. Amplification factors as great as 10(12) are predicted for the highest-Q microsphere resonators. The analytic theory of these devices is presented.
authors: B E
authors: BE
authors: Little
authors: S T
authors: ST
authors: Chu
authors: H A
authors: HA
authors: Haus