• Title/Summary/Keyword: photonic crystal fiber

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Study of Photonic Crystal Waveguide in Microwave Regime Using 3D FDTD Simulation (3차원 FDTD모사를 이용한 마이크로웨이브 영역에서의 광결정 도파로에 관한 연구)

  • Han, Seung-Ho;Park, Q-Han;Roh, Young-Geun;Heonsu leon
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.184-185
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    • 2003
  • Unlike the conventional waveguide such as optical fiber using total internal reflection, photonic crystal waveguide(PCW), a waveguide made of a line defect in a photonic crystal(PC) structure, does not admit an analytic approach due to its complexity but requires a direct numerical approach. Here, we present numerical results of computer simulation for PCW by using the three-dimensional(3D) Finite-Difference Time -Domain(FDTD) algorithm. (omitted)

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Investigation of an Arc-induced Long Period Fiber Grating Inscribed in a Photonic Crystal Fiber with Two Large Air Holes

  • Kim, Sun-Duck;Kim, Gil-Hwan;Hwang, Kyu-Jin;Lim, Sun-Do;Lee, Kwan-Il;Kim, Sang-Hyuck;Lee, Sang-Bae
    • Journal of the Optical Society of Korea
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    • v.13 no.4
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    • pp.428-433
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    • 2009
  • A photonic crystal fiber with two large air holes outside the holey cladding region is fabricated to induce an effective long periodic grating (LPG) in the core by an electric arc discharge. We believe that the two large air holes lead to the asymmetric perturbation in the core under the electric arc discharge, thereby introducing the coupling to the first higher-order mode. The transmission characteristics of the PCF with the LPG for the external perturbation such as strain, curvature, and temperature are also investigated. It was found that the shift of resonance peak in the transmission spectrum depends on the bending direction. The curvature of 8.55 $m^{-1}$ results in the center wavelength shifts of 1.8, 4.3, and 11 nm for a vertical, diagonal, and horizontal direction of the curvature to the large air-hole alignment, respectively.

Simulation of the Structural Parameters of Anti-resonant Hollow-core Photonic Crystal Fibers

  • Li, Qing;Feng, Yujun;Sun, Yinhong;Chang, Zhe;Wang, Yanshan;Peng, Wanjing;Ma, Yi;Tang, Chun
    • Current Optics and Photonics
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    • v.6 no.2
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    • pp.143-150
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    • 2022
  • Anti-resonant hollow-core photonic crystal fiber (AR-HCF) has unique advantages, such as low nonlinearity and high damage threshold, which make it a promising candidate for high-power laser delivery at distances of tens of meters. However, due to the special structure, optical properties such as mode-field profile and bending loss of hollow-core fibers are different from those of solid-core fibers. These differences have limited the widespread use of AR-HCF in practice. In this paper we conduct numerical analysis of AR-HCFs with different structural parameters, to analyze their influences on an AR-HCF's optical properties. The simulation results show that with a 23-㎛ air-core diameter, the fundamental mode profile of an AR-HCF can well match that of the widely used Nufern's 20/400 fiber, for nearly-single-mode power delivery applications. Moreover, with the ratio of cladding capillary diameter to air-core diameter ranging from 0.6 to 0.7, the AR-HCF shows excellent optical characteristics, including low bending sensitivity while maintaining single-mode transmission at the same time. We believe these results lay the foundation for the application of AR-HCFs in the power delivery of high power fiber laser systems.

Supercontinuum Generation with Femtosecond Pulses and Photonic Crystal Fibers (펨토초 펄스와 광결정 광섬유를 이용한 초 연속스펙트럼의 발생)

  • Choi, Hyoung-Gye;Kim, So-An;Kee, Chul-Sik;Sung, Jae-Hee;Yu, Tae-Jun;Ko, Do-Kyeong;Lee, Jong-Min
    • Korean Journal of Optics and Photonics
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    • v.18 no.5
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    • pp.345-350
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    • 2007
  • The characteristics of the supercontinuum generated in photonic crystal fibers were investigated by using the generalized nonlinear $Schr\"{o}dinger$ equation and the split-step Fourier method. Based on the simulated results, we generated the supercontinuum spectrum with the flatness of ${\pm}4dB$ in the wavelength range of 650 to 900 nm by employing a 200-fs pulse of Ti:sapphire laser and a commercial photonic crystal fiber.

Polarization-Maintaining Photonic-Crystal-Fiber-based Polarimetric Strain Sensor with a Short Sensing Head (짧은 센서부를 가진 편광유지 광자결정 광섬유 기반 편광 간섭형 스트레인 센서)

  • Noh, Tae Kyu;Lee, Yong Wook
    • Korean Journal of Optics and Photonics
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    • v.25 no.3
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    • pp.131-136
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    • 2014
  • In this paper we have implemented a temperature-insensitive polarimetric fiber strain sensor based on a Sagnac birefringence interferometer composed of a short polarization-maintaining photonic crystal fiber (PM-PCF), a 3-dB fiber coupler, and polarization controllers. The PM-PCF used as a sensor head was 2 cm long, which is the shortest length for a sensing element compared to other polarimetric fiber strain sensors using a PM-PCF. The proposed sensor showed a strain sensitivity of ${\sim}0.87pm/{\mu}{\varepsilon}$ with a strain measurement range from 0 to $8m{\varepsilon}$. The temperature sensitivity was also investigated and measured as approximately $-12pm/^{\circ}C$, when ambient temperature changed from 30 to $100^{\circ}C$. This temperature sensitivity is about 82 times smaller than that of conventional polarization-maintaining fiber (approximately $-990pm/^{\circ}C$). In particular, from a practical perspective we have experimentally and theoretically confirmed that the wavelength selected for the indicator dip location does not make a significant difference in the strain sensitivity.

Highly-birefringent Photonic Crystal Fiber with Squeezed Lattice for Strain, Curvature and Temperature Sensing (큰 복굴절 특성을 가지는 광자결정 광섬유를 이용한 스트레인, 구부림 및 온도 특성)

  • Eom, Sung-Hoon;Kim, Gil-Hwan;Hwang, Hyu-Jin;Ma, Kyung-Sik;Lee, Kwan-Il;Jeong, Je-Myung;Lee, Sang-Bae
    • Korean Journal of Optics and Photonics
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    • v.21 no.6
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    • pp.230-234
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    • 2010
  • Highly-Birefringent Photonic Crystal Fiber (Hi-Bi PCF) is composed of a single material, silica, so that its temperature sensitivity is extremely low. Therefore, we propose afiber based Sagnac interferometer for measurement of strain and curvature independent of temperature variation. The sensitivities of strain and curvature (both axes) are measured to be $1.41\;pm/{\mu}{\varepsilon}$ and $0.93nm/m^{-1}$(slow axis Y), $-1.6\;nm/m^{-1}$(fast axis X), respectively.

Midinfrared Pulse Compression in a Dispersion-decreasing and Nonlinearity-increasing Tapered As2S3 Photonic Crystal Fiber

  • Shen, Jianping;Zhang, Siwei;Wang, Wei;Li, Shuguang;Zhang, Song;Wang, Yujun
    • Current Optics and Photonics
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    • v.5 no.3
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    • pp.250-260
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    • 2021
  • A tapered As2S3 photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As2S3 PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 ㎛ propagating in the tapered PCF are located in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As2S3 PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.

Dependence of the Transmission Characteristics of Photonic Crystal Fiber on the Macrobending Radius and the Mechanically Induced Microbending

  • Lee, Byeong-Ha;Moon, Dae-Seung;Eom, Joo-Beom;Kim, Jin-Chae;Kim, Hok-Young;Paek, Un-Chul
    • Journal of the Optical Society of Korea
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    • v.7 no.2
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    • pp.72-78
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    • 2003
  • It is reported that the spectral loss of photonic crystal fiber (PCF) having a large hole-to-hole distance (~ 10 ${\mu}{\textrm}{m}$) is sensitive to micro- and macrobending when compared with the conventional single-mode fiber. In this paper, we will present the measurement result of the macro- and microbending characteristics of fabricated PCF with large hole-to-hole distance (> 10 ${\mu}{\textrm}{m}$) . For the macrobending experiment, the fiber was simply wound around a circular structure with variable diameter that could be reduced to a few centimeters. For the microbending case, regularly spaced silica rods were attached on a slide glass and pressed against the fiber by loading a stack of metal plates of known weight on the glass. The transmission loss spectrum shows a rather flat response to the to microbending, and this makes the PCF a good candidate for a wideband variable optical attenuator.