상세정보
학술지
Noncontact detection of ultrasonic waves using fiber optic Sagnac interferometer
- 발행일
- 200206
- 출처
- IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, v.49 no.6, pp.767-775
- ISSN
- 0885-3010
- 출판사
- IEEE
- 협약과제
- 02MT2300, 테라급 광회선분배 시스템 (OXC) 기술, 김광준
- 초록
- This paper describes a fiber optic sensor suitable for noncontact detection of ultrasonic waves. This sensor is based on the fiber optic Sagnac interferometer, which has a path-matched configuration and does not require active stabilization. Quadrature phase bias between two interfering lasor beams in the Sagnac loop is applied by controlling the birefringence using a fiber polarization controller. A stable quadrature phase bias can be confirmed by observing the interferometer output according to the change of phase bias. Additional signal processing is not needed for the detection of ultrasonic waves using the Sagnac interferometer. Ultrasonic oscillations produced by conventional ultrasonic piezoelectric transducers were successfully detected, and the performance of this interferometer was investigated by a power spectrum analysis of the output signal. Based on the validation of the fiber optic Sagnac interferometer, noncontact detection of laser-generated surface waves was performed. The configured Sagnac interferometer is very effective for the detection of small displacement with high frequency, such as ultrasonic waves used in conventional nondestructive testing (NDT).