title: Continuous-wave fiber cavity ring-down measurements using frequency-shifted interferometry.
abstract: We present a spatial-domain fiber cavity ring-down (CRD) technique that does not require optical pulses for time-resolved detection. Instead of measuring the intensity decay rate of an optical pulse in the time domain as in conventional CRD experiments, we measure the decay rate of a CW signal in a ring-down cavity (RDC) using frequency-shifted interferometry in the spatial domain, as a function of distance traveled by the light. As a proof-of-concept demonstration, we measured fiber bend loss in a loop RDC using this technique, and a cavity loss change as low as 0.0135 dB induced by every fiber turn on a mandrel was unambiguously discerned.
authors.affiliation: The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada. fei.ye@utoronto.ca
authors.forename: Fei
authors.initials: F
authors.lastname: Ye
authors.forename: Bing
authors.initials: B
authors.lastname: Qi
authors.forename: Li
authors.initials: L
authors.lastname: Qian