서지주요정보
마하젠더 간섭계와 이중모드 광섬유 간섭계를 이용한 센서에 관한연구 = Fiber-optic sensors using Mach-Zehnder interferometer and two-mode fiber-optic interferometer
서명 / 저자 마하젠더 간섭계와 이중모드 광섬유 간섭계를 이용한 센서에 관한연구 = Fiber-optic sensors using Mach-Zehnder interferometer and two-mode fiber-optic interferometer / 김봉규.
저자명 김봉규 ; Kim, Bong-Kyu
발행사항 [대전 : 한국과학기술원, 1996].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8006860

소장위치/청구기호

학술문화관(문화관) 보존서고

DPH 96021

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Fiber-optic sensors for measuring voltage, strain and temperature have been demonstrated by using a Mach-Zehnder interferometer and a two-mode fiber-optic interferometer. While a Mach-Zehnder interferometer is the most straight forward approach, a two-mode fiber-optic interferometer allows the realization of very useful sensors that are difficult to make using conventional single-mode fiber-optic technology. A fiber-optic voltage sensor based on the Mach-Zehnder interferometer has been demonstrated with a new signal processing scheme, which displays the magnitude as well as the waveform of applied voltage with immunity from the signal frequency change. The sensing element was formed using a PZT phase modulator. The voltage was measured by counting the number of fringe shift during a half period of applied signal. The sensor showed a linear response to the applied voltage. The temperature dependence of the sensor output was experimentally evaluated over the temperature range from -20℃ to 80℃. It was demonstrated that the detrimental polarization modulation effect could be overcome by using polarization maintaining fibers or a half-wave plate in the phase modulator. The polarization signal fading could be avoided by using a rotating polarizer at the interferometer output. For two-mode fiber-optic interferometric sensors, the polarization and modal characteristics of a two-mode fiber with a highly elliptical core were studied. We measured the cutoff wavelengths of the second-order mode($LP_{11}^{even}}$) for two polarization states, the beatlengths between two spatial modes (${rm LP_{01}}$ and ($LP_{11}$) for two polarization states, and the polarization beatlength of the fundamental mode. Large polarization dependances of the cutoff wavelength and the beatlengths were measured. The large difference of the cutoff wavelengths for two polarization states can be utilized for a new type polarizer. The differential phase shift between two modes induced by strain and temperature change was measured. We observed a large nonlinear response of the differential phase shift between the two spatial modes to the fiber elongation when the optical wavelength is near the cutoff wavelength $(λ_c)$ of the $LP_{11}}$ mode. It has been analyzed experimentally and theoretically that the nonlinearity increases dramatically as the wavelength approaches the cutoff wavelength. The nonlinear strain response is an important factor for the design of two-mode fiber-optic strain sensors and new applications may be possible based on the effect.

서지기타정보

서지기타정보
청구기호 {DPH 96021
형태사항 iv, 145 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Bong-Kyu Kim
지도교수의 한글표기 : 김병윤
지도교수의 영문표기 : Byoung-Yoon Kim
학위논문 학위논문(박사) - 한국과학기술원 : 물리학과,
서지주기 참고문헌 : p. 138-145
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