• Title/Summary/Keyword: Fiber gratings

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Fabrication of Various Fiber Bragg Gratings Using the UV-Argon Laser (제2고조파 Argon Laser를 이용한 여러 가지 광섬유 격자의 제작)

  • 김승우;권재중;김성철;이병호
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.309-312
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    • 1999
  • Fiber Bragg gratings have many applications such as fiber sensors, band-stop filters, add-drop filters, and mode convertors. In this paper, we present the fabrication method of various fiber Bragg gratings by using continuous wave UV-Argon(frequency-doubled Argon) laser. In our experiments, hydrogenation of fibers was used to enhance photosensitivity of fiber. And we fabricated fiber gratings by the phase mask method.

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Design of narrow band-pass filter using two fiber bragg gratings (광섬유 격자소자를 이용한 협대역 투과 필터의 설계)

  • 임종훈;이경식
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.8
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    • pp.82-88
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    • 1998
  • We propose and design a new type of anrrow band-pass optical filter based on two fiber gratings with different reflection wavelength. The ripples occur in the spectra of the filter with two uniform fiber gratings. Our simulation results also show that the ripples disappear with the fiber gratings apodized to both gaussian and hyperbolic tangent function. The hyperbolic tangent function seems to be a better apodization function for improving the filter's performance in terms of narrow pass bandwidth and high transmission.

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Novel Long-period Fiber Grating devices for Monitoring the Deformation of Ship Hull (선체의 변형을 감지하기 위한 새로운 형태의 장주기 광섬유 격자 소자)

  • Sohn, Kyung-Rak
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.6
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    • pp.761-767
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    • 2007
  • We have developed novel optical-fiber sensors based on strain-induced long-period fiber gratings for monitoring the deformation of a hull. They have no external pressure for sustaining the mechanical formed gratings. The pressure, which provides a force to form the periodic grating along the single mode fiber, was realized by the bonding strength of a photopolymer. To reduce the polarization dependency of the sensors caused by the asymmetry structure of gratings, a Faraday Rotator Mirror (FRM) was utilized in this experiment. We have realized the polarization-insensitive function of the proposed sensors. The change of an external strain are measured by an optical spectrum analyzer. When the external stain increases. the attenuation at the resonant wavelength decreases and the loss peak was slightly shifted to the shorter wavelength.

Basic Study on The Long-period Fiber Grating Pressure Sensor for applying the Vessels (선박적용을 위한 장주기 광섬유 격자 압력센서의 기초연구)

  • Sohn, Kyung-Rak;Choi, Young-Gil;Jang, Se-In;Choi, Jae-Yun
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.11a
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    • pp.202-203
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    • 2005
  • we present a pressure sensor based on the mechanically formed long-period fiber gratings. The attenuation properties of an output power as a function of an external pressure is able to apply to the in-line fiber pressure sensors for the vessels.

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Application passband filter of multiply cascaded phase-shifted long-period fiber gratings

  • Kim, Min-Sung;Han, Young-Geun;Kang, Dong-Joong;Ha, Jong-Eun;Kim, Jin-Young;Lho, Tae-Jung
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2496-2498
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    • 2005
  • The transmission characteristics of multiply cascaded phase-shifted long-period fiber gratings (LPFGs) will be investigated theoretically and experimentally. Their passband can be changed by increasing the number of ${\pi}$ -shifted LPFGs. When two ${\pi}$ -shifted LPFGs with different grating lengths are cascaded in series, the bandwidth of the rejection band and passband can be controlled by the pristine characteristics of two gratings.

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Multipoint Pressure-detection Sensors using Microbanding-induced Long-period Fiber Gratings (마이크로밴딩 장주기 광섬유 격자를 이용한 다중위치 압력감지 센서)

  • Sohn, Kyung-Rak;Choi, Young-Gill;Jang, Se-In;Choi, Jae-Yun;Shim, Joon-Hwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.3
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    • pp.449-454
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    • 2006
  • We present a pressure sensor based on the mechanically induced long-period fiber gratings (LPFG) for detecting the multi-location strain variation. The theoretical analysis is performed using a graphic method for a weakly guiding step-index fiber. The calculated results are in good agreement with the experimental results. In this study, from the fact that the optical parameters of a single-mode fiber slightly differ from manufacturing company to manufacturing company, the multipoint pressure-detection sensor systems composed two identical LPFGs are realized. When the pressure is applied two LPFG sensors at once, the resonance peaks are separated as much as about 40 nm. These types of sensor systems are well suited as a multipoint monitoring of strain or temperature in the ship or the smart structure.

Effects of Gamma Radiation on Fiber Bragg Gratings by the Fiber Re-coating Methods (광섬유 브래그 격자의 재코팅 방법에 따른 감마 방사선의 영향)

  • Kim, Jong-Yeol;Lee, Nam-Ho;Jung, Hyun-Kyu
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.782-784
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    • 2016
  • In this study, we studied the gamma-radiation effect of fiber Bragg gratings on the fiber re-coating methods. The fiber Bragg gratings were exposed to gamma-radiation up to a dose of 100 kGy at the dose rate of 104 Gy/min. In our experimental results, we confirmed that the fiber acrylate re-coating process leads to a slightly lower radiation sensitivity of FBGs.

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Novel Raman Fiber Laser and Fiber-Optic Sensors Using Multi-Channel Fiber Gratings

  • Han, Young-Geun;Kim, Sang-Hyuck;Lee, Sang-Bae;Kim, Chang-Seok;Kang, Jin-U.;Paek, Un-Chul;Chung, Young-Joo
    • Journal of the Optical Society of Korea
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    • v.7 no.2
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    • pp.97-101
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    • 2003
  • The transmission characteristics of multi-channel long period fiber gratings (LPFGs) in terms of the physical parameters like the separation distance, grating length and number of gratings will be discussed. Their transmission characteristics such as channel spacing, number of channels, loss peak depth, and channel bandwidth can be easily controlled by physical parameters. Based on the experimental results, their applications to optical multiwavelength Raman lasers and optical sensors will be investigated. A multiwavelength Raman fiber ring laser with 9 WDM channels with 100 ㎓ spacing and 19 channels with 50 ㎓ spacing using tunable multi-channel LPFGs will be experimentally demonstrated. The fiber-optic sensing applications with high resolution and sensitivity based on multi-channel LPFGs will be also presented.

Long-Period Fiber Gratings Based on Periodically Surface-Etched Structure Imprinted by Using a Photoresist Polymer (폴리머 장주기 패턴을 이용한 표면 식각된 격자 구조 기반의 장주기 광섬유 격자)

  • Park, Sang-Oh;Kwon, Oh-Jang;Han, Young-Geun
    • Korean Journal of Optics and Photonics
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    • v.22 no.1
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    • pp.1-4
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    • 2011
  • A new fabrication technique of long-period fiber gratings with periodically surface-etched structures is proposed. Transmission characteristics of the periodically surface-etched long-period fiber gratings are improved by changing strain because of variation of coupling strength between the core and the cladding modes. The sensitivities of the periodically surface-etched long-period fiber gratings to strain, torsion, and ambient refractive index were measured. The strain and the torsion sensitivities were measured to be $-0.033\;dB/\mu\varepsilon$ and -1.30 nm m/rad, respectively. The ambient index sensitivity was measured to be -31.33 nm/RIU from a range from 1.33 to 1.42.

Fiber Brags Grating Fabrication using Interferometer with Phase Mask (위상 마스크 간섭계를 이용한 광섬유 격자 제작)

  • 유계준;이호준;김병규;김선관;이원준
    • Proceedings of the Optical Society of Korea Conference
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    • 2001.02a
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    • pp.194-195
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    • 2001
  • We fabricated fiber bragg gratings using interferometric method with Phase mask. The interferometer consisted of two plane-parallel mirrors and a phase mask perpendicular to mirrors. The Gratings were written using an Argon-ion laser. The experimental setup could change Bragg wavelength given by the phase mask. (omitted)

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