Bandwidth-tunable band-rejection filter based on helicoidal fiber grating pair of opposite helicities

Shin, Woojin; Yu, Bong-Ahn; Noh, Young Chul; Lee, Jongmin; Ko, Do‐Kyeong; Oh, Kyunghwan

doi:10.1364/ol.32.001214

Cited by 62 publications

(12 citation statements)

References 10 publications

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“…5,9,22,171,172 Normal LPFG-based filters, however, allow tuning of only resonance wavelength or attenuation amplitude. 5,22,53 Shin et al 160 developed a bandwidth-tunable band-rejection filter consisting of a CO 2 -laser-induced helicoidal LPFG pair of opposite helicities, as shown in Fig. 23.…”

Section: A Band-rejection Filtersmentioning

confidence: 99%

Review of long period fiber gratings written by CO2 laser

Wang

2010

Journal of Applied Physics

222

134

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This paper presents a systematic review of long period fiber gratings (LPFGs) written by the CO2 laser irradiation technique. First, various fabrication techniques based on CO2 laser irradiations are demonstrated to write LPFGs in different types of optical fibers such as conventional glass fibers, solid-core photonic crystal fibers, and air-core photonic bandgap fibers. Second, possible mechanisms, e.g., residual stress relaxation, glass structure changes, and physical deformation, of refractive index modulations in the CO2-laser-induced LPFGs are analyzed. Third, asymmetrical mode coupling, resulting from single-side laser irradiation, is discussed to understand unique optical properties of the CO2-laser-induced LPFGs. Fourthly, several pretreament and post-treatment techniques are proposed to enhance the efficiency of grating fabrications. Fifthly, sensing applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based temperature, strain, bend, torsion, pressure, and biochemical sensors. Finally, communication applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based band-rejection filters, gain equalizers, polarizers, and couplers.

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Section: A Band-rejection Filtersmentioning

confidence: 99%

Review of long period fiber gratings written by CO2 laser

Wang

2010

Journal of Applied Physics

222

134

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“…By twisting the fiber during CO 2 -laser exposure, a helicoidal LPFG can be formed, where the codirectional and contradirectional torsions of the fiber result in spectral shifts to shorter and longer wavelength, respectively. A flexible band-rejection filter with a tunable bandwidth can be achieved by connecting a pair of helicoidal gratings of opposite helicities in series [23]. By connecting two helicoidal gratings of the same helicity to the two ends of a hollow-core fiber, however, a tunable bandpass filter can be realized [24].…”

Section: Lpfg Written In Conventional Smfmentioning

confidence: 99%

Recent development on CO 2 -laser written long-period fiber gratings

Liu

Chiang

2008

Passive Components and Fiber-Based Devices V

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The paper reviews the recent progress on CO 2 -laser writing of long-period fiber gratings (LPFGs) in different kinds of fibers, including conventional single-mode fiber (SMF), boron-doped SMF, polarization-maintaining fiber, photonic crystal fiber, and polarization-maintaining photonic crystal fiber. In particular, we report the writing dynamics for the understanding of the physical mechanisms involved in the writing process and show that the CO 2 -laser pulses can not only relax the internal stress in the fiber core but also induce a frozen-in stress in the cladding of the fiber under tension. The applications of CO 2 -laser written LPFGs, especially for the realization of broadband optical couplers, are also discussed.

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“…Thus, it is necessary to break the symmetry of fiber devices to construct sensitivity-improved torsion sensors while maintaining their direction discrimination. In recent years, helical structures have been implemented in optical fibers to demonstrate novel strain sensors [5], twist sensors [6][7][8], and tunable filters [9]. Some of these devices have been realized by employing photonic crystal fibers (PCFs) [10][11][12][13] and exhibited good torsion-sensing characteristics as well.…”

Section: Introductionmentioning

confidence: 99%

Helicity Enhanced Torsion Sensor Based on Liquid Filled Twisted Photonic Crystal Fibers

Zhang

Wang

Bai

et al. 2020

Sensors

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A highly sensitive torsion sensor can be constructed by combining a twisted photonic crystal fiber with a liquid-filled waveguide in its air-hole cladding. The torsion sensitivity of this type of sensor is determined directly by the phase-matching conditions between the fiber core mode and the liquid waveguide mode, which can be improved by tuning the helicity (denoted by the initial twist rate, α 0 ) of the twisted photonic crystal fiber. The enhancement mechanism of α 0 on the sensitivity of the proposed torsion sensor is investigated theoretically, followed by experimental verifications, and a torsion sensitivity as high as 446 nm·mm·rad −1 can be obtained by tailoring these parameters. Experimental results show that the torsion sensitivity increases with α 0 decreasing from 3.142 to 3.925 rad/mm, which are in consistence with that of the numerical predictions. The demonstrated torsion sensor is expected to contribute to the development of highly sensitive torsion-related photonic crystal fiber devices.

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Bandwidth-tunable band-rejection filter based on helicoidal fiber grating pair of opposite helicities

Cited by 62 publications

References 10 publications

Review of long period fiber gratings written by CO2 laser

Review of long period fiber gratings written by CO2 laser

Recent development on CO 2 -laser written long-period fiber gratings

Helicity Enhanced Torsion Sensor Based on Liquid Filled Twisted Photonic Crystal Fibers

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