Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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FBG Sensor Demodulation Using a Double-Pass Mach-Zhender Interferometer

더블패스 마하젠더 간섭계를 이용한 광섬유 격자 센서의 파장복조

  • Park, Hyoung-Jun (Divison of Electronics and Information Engineering, Chonbuk National University) ;
  • Song, Min-Ho (Divison of Electronics and Information Engineering, Chonbuk National University)
  • 박형준 (전북대학교 전자정보공학부) ;
  • 송민호 (전북대학교 전자정보공학부)
  • Published : 2007.08.30
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Abstract

A wavelength-demodulation algorithm for FBG sensor is proposed by using a double-pass Mach-Zehnder interferometer. Zero-crossing points of double-passed interference signal are used to trigger the accurate $90^{\circ}C$ phase difference positions in the sensor signal, which is an essential condition in the subsequent arctangent and phase unwrapping signal processing. With the proposed method, we could efficiently measure various measurands, such as dynamic-, static-strain, and temperature, and ${\sim}8pm$ of wavelength resolution was obtained.

마하젠더 간섭계를 왕복한 간섭신호를 영점검출하여 광섬유 격자 센서의 신호처리를 위한 기준 트리거로 사용하는 방법을 제안하였다. 영점 트리거에 의해서 얻은 센서신호로부터 측정 물리량에 선형적으로 비례하는 위상성분을 추출하여 간단한 구조로도 정밀하게 광섬유격자의 파장변화를 감지할 수 있는 복조방식을 구현하였다. 제안한 복조방식을 적용하면 위상변조의 속도나 비선형성, 또는 환경적 외란에 관계없이 광섬유 격자 센서에 가해지는 동적, 정적 변형률과 온도변화를 효율적으로 측정할 수 있음을 실험적으로 증명하였으며, 실험결과로부터 계산된 센서시스템의 파장측정 분해능은 8 pm이었다.

Keywords

References

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