서지주요정보
Characterization of long-period fiber grating written by modal-interference pattern of guided light = 도파모드의 간섭무늬를 이용하여 새긴 장주기 광섬유 격자에 대한 연구
서명 / 저자 Characterization of long-period fiber grating written by modal-interference pattern of guided light = 도파모드의 간섭무늬를 이용하여 새긴 장주기 광섬유 격자에 대한 연구 / Jung-Huyng Pyo.
저자명 Pyo, Jung-Huyng ; 표정형
발행사항 [대전 : 한국과학기술원, 1999].
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소장정보

등록번호

8010370

소장위치/청구기호

학술문화관(문화관) 보존서고

MPH 99031

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초록정보

Long-period fiber gratings have been widely used as wavelength filters in optical fiber communication and fiber optic sensor systems. In this thesis, we demonstrate a long-period fiber grating that couplies core-mode to cladding-modes in the infrared region, which is written by the modal-interference pattern of guided light of 488 nm wavelength. The modal-interference pattern along the fiber induces permanent refractive index change in the Ge-doped photosensitive fiber. Theoretical calculation has been carried out and showed that the grating has resonant coupling at multiple wavelengths as well as the writing wavelength, where the phase matching condition is satisfied. In the experiment, elliptical-core fiber with cutoff wavelength of 630 nm was used. The fiber was hydrogen-loaded for high photosensitivity. The grating was written using interference pattern of $LP_01$ and $LP_11$ core modes at 488 nm. The fabricated grating showed 99% coupling efficiency between the two core modes for the grating length of 50 cm at the writing wavelength. The coupling between $LP_01$ core-mode and cladding mode was observed in infrared region, at the wavelengths of 867.25, 869.65, 873.25, 875.5 nm. At each wavelength, the coupling efficiency and the 3-dB spectral bandwidth was about 60% and 1.5 nm, respectively. The four wavelengths correspond to coupling to two different cladding modes for two orthogonal polarization states of the input light. This method makes it possible to fabricate a long-period grating with total length of more than tens of centimeter using blue-green laser wavelengths, that can be used at infrared wavelength. The coupling wavelengths can be shifted to the communication wavelengths of 1.3 or 1.55㎛, if a fiber with proper paramenter for the required phase matching condition is used.

서지기타정보

서지기타정보
청구기호 {MPH 99031
형태사항 [iv], 57 p. : 삽도 ; 26 cm
언어 영어
일반주기 저자명의 한글표기 : 표정형
지도교수의 영문표기 : Byoung-Yoon Kim
지도교수의 한글표기 : 김병윤
학위논문 학위논문(석사) - 한국과학기술원 : 물리학과,
서지주기 Reference : p. 50-57
주제 Optical fiber
Mode coupling
Filter
Long period grating
광섬유
모드 결합
파장필터
장주기 격자
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