• 한국인터넷방송통신학회논문지
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• 제24권5호
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• pp.141-146
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• 2024

이중주기 격자로 구성된 GMR 필터의 동적 특성을 탐구하였다. 각 주기 내에 반사와 투과 특성을 발생시키는 여러 개의 글로브와 슬릿으로 구성된 격자를 고려하였다. 제안한 복합 격자는 이중주기 격자의 수에 의존하여 주어진 TE, TM 모드의 회절 차수를 상쇄할 뿐만 아니라 강화하도록 설계될 수 있는 것으로 나타났다. 회절 전력의 일반적인 특성을 도출하기 위하여 고유치 문제에 기초한 모드 전송 선로 이론을 적용하여 수치해석 하였다. 수치해석 결과 NIR 광 대역 필터, 방사체 및 흡수체 설계에 유용한 복합 구조의 공진 모드를 선택적으로 조작하여, 간단하고 효과적인 GMR 필터를 구현할 수 있음을 확인하였다.

• Current Optics and Photonics
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• 제5권3호
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• pp.243-249
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• 2021

In this paper, the sensing characteristics of a double cladding fiber (DCF) long-period fiber grating (LPFG) to the surrounding refractive index (SRI) are studied. The outer cladding of the DCF plays the role of the overlay, thus, the mode transition (MT) phenomenon of DCF can be induced by etching the outer cladding radius instead of coating overlays. The response characteristics of the effective refractive index (ERI) of the cladding mode to the outer cladding radius are analyzed. It is found that in the MT range, the change rate of ERIs of cladding modes is relatively larger than that for other ranges. Further, based on the features of the mode transition region (MTR), the phase-matching curve of the 11^th cladding mode is investigated, and the response of the DCF-LPFG to the SRI is characterized by the change of wavelength intervals between the dual peaks under different outer cladding radii. The numerical simulation results show that the SRI sensitivity is greatly improved, which is available to 3484.0 nm/RIU with the fitting degree 0.998 in the SRI range of 1.33-1.37. The proposed DCF-LPFG can provide new theoretical support for designing the DCF-LPFG refractive index sensor with excellent performances of sensitivity, linearity and structure.

• 전기학회논문지
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• 제56권11호
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• pp.1995-1997
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• 2007

In this paper we propose a wavelength-switchable fiber ring laser that employs a polarization-dependent fiber band stop filter. The fiber filter was fabricated by inscribing a long-period fiber grating on a high birefringent fiber. Dual-wavelength switching operation was accomplished by controlling the rotatable linear polarizer which rotated the polarization plane of the light circulating through the fiber laser cavity. The amplitude variation of both laser lines was measured to be less than 0.5 dB and the signal-to-amplified spontaneous emission ratio was more than 55 dB.