The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jes Broeng - One of the best experts on this subject based on the ideXlab platform.
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single frequency ytterbium doped Photonic Bandgap fiber amplifier at 1178 nm
Optics Express, 2012Co-Authors: Mingchen Chen, Christina B Olausson, Akira Shirakawa, Jens K Lyngso, Kenichi Ueda, Xinyan Fan, Jes BroengAbstract:1178 nm single-frequency amplification by Yb doped Photonic Bandgap fiber has been demonstrated. 24.6 W output power and 12 dB gain were obtained without parasitic lasing and also stimulated Brillouin scattering. 1.8 dB suppression of Brillouin gain by an acoustic antiguiding effect has been found in the Yb doped Photonic Bandgap fiber.
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167 w power scalable ytterbium doped Photonic Bandgap fiber amplifier at 1178nm
Optics Express, 2010Co-Authors: Christina B Olausson, Araceli Bjarklev, Jes Broeng, Akira Shirakawa, Meishin Chen, Jens K Lyngso, K P Hansen, Kenichi UedaAbstract:An ytterbium-doped Photonic Bandgap fiber amplifier operating at the long wavelength edge of the ytterbium gain band is investigated for high power amplification. The spectral filtering effect of the Photonic Bandgap efficiently suppresses amplified spontaneous emission at the conventional ytterbium gain wavelengths and thus enables high power amplification at 1178 nm. A record output power of 167 W, a slope efficiency of 61% and 15 dB saturated gain at 1178 nm have been demonstrated using the ytterbium-doped Photonic Bandgap fiber.
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high power yb doped Photonic Bandgap fiber amplifier at 1150 1200 nm
Optics Express, 2009Co-Authors: Akira Shirakawa, Christina B Olausson, Jens K Lyngso, Kenichi Ueda, Hiroki Maruyama, Jes BroengAbstract:Ytterbium-doped solid-core Photonic Bandgap fiber amplifiers operating at the long-wavelength edge of the ytterbium gain band are reported. The low-loss Bandgap transmission window is formed in the very low gain region, whilst outside the Bandgap, large attenuation inhibits the exponential growth of amplified spontaneous emission in the huge-gain 1030-1100 nm region. Hence parasitic-lasing-free, high-power amplification with a marked efficiency is enabled. A 32 W output at 1156 nm with a 66% slope efficiency and 30 W output at 1178 nm with a 58% slope efficiency were successfully obtained. To our knowledge, these are the highest output powers generating from active Photonic Bandgap fibers, as well as from ytterbium-doped fiber lasers at these wavelengths.
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all fiber chirped pulse amplification using highly dispersive air core Photonic Bandgap fiber
Optics Express, 2003Co-Authors: C J S De Matos, T.p. Hansen, K P Hansen, J R Taylor, Jes BroengAbstract:We show, for the first time to our knowledge, all-fiber chirped pulse amplification using an air-core Photonic Bandgap fiber. Pulses from a wavelength- and duration-tunable femtosecond/picosecond source at 10 GHz were dispersed in 100 m of dispersion compensating fiber before being amplified in an erbium-doped fiber amplifier and subsequently recompressed in 10 m of the anomalously dispersive Photonic Bandgap fiber. Pulses as short as 1.1 ps were obtained. As air-core fibers present negligible nonlinearity, the presented configuration can potentially be used to obtain ultra-high pulse peak powers. A study of the air-core fiber dispersion and dispersion slope is also presented.
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analysis of air guiding Photonic Bandgap fibers
Optics Letters, 2000Co-Authors: Jes Broeng, Stig Eigil Barkou, Thomas Sondergaard, Araceli BjarklevAbstract:We present what is to our knowledge the first theoretical analysis of air-guiding Photonic Bandgap fibers. The fibers are characterized by a large hollow core and a microstructured cladding exhibiting Photonic Bandgap effects. Using an efficient, full-vectorial numerical method, we explain the operational principle of the fibers and obtain detailed information about the properties of the air-guided modes. This information includes accurate determination of the modes’ spectral extent, cutoff properties, and mode-field distributions.
Kunimasa Saitoh - One of the best experts on this subject based on the ideXlab platform.
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large mode area all solid Photonic Bandgap fibers for the mitigation of optical nonlinearities
IEEE Journal of Selected Topics in Quantum Electronics, 2016Co-Authors: Liang Dong, Thomas W Hawkins, Maxwell Jones, Monica T Kalichevskydong, Benjamin Pulford, Joshua Parsons, Fanting Kong, Guancheng Gu, Kunimasa Saitoh, Iyad DajaniAbstract:There is still significant need for power scaling of fiber lasers. Large-mode-area fibers are a key for the mitigation of optical nonlinearities. In recent years, mode instability has shown itself to be an additional significant limiting factor for single-mode power scaling in the regime of a few hundred watts to kilowatts. It is better appreciated now that further power scaling requires significant high-order-mode suppression in addition to a large effective mode area in a fiber. In recent years, we have shown that all-solid Photonic Bandgap fibers are a superior approach due to their unsurpassed higher-order-mode suppression in large-mode-area designs, making them well suited for applications at high average powers. We will review of some of the recent progress, challenges, and prospects of all-solid Photonic Bandgap fibers in this invited paper.
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ytterbium doped large mode area all solid Photonic Bandgap fiber lasers
Optics Express, 2014Co-Authors: Fanting Kong, Maxwell Jones, Monica T Kalichevskydong, Joshua Parsons, Thomas Hawkins, Kunimasa Saitoh, Christopher Dunn, Liang DongAbstract:Single-mode operation in a large-mode-area fiber laser is highly desired for power scaling. We have, for the first time, demonstrated a 50μm-core-diameter Yb-doped all-solid Photonic Bandgap fiber laser with a mode area over 4 times that of the previous demonstration. 75W output power has been generated with a diffraction-limited beam and an efficiency of 70% relative to the launched pump power. We have also experimentally confirmed that a robust single-mode regime exists near the high frequency edge of the Bandgap. These fibers only guide light within the Bandgap over a narrow spectral range, which is essential for lasing far from the gain peak and suppression of stimulated Raman scattering. This work demonstrates the strong potential for mode area scaling of in single-mode all-solid Photonic Bandgap fibers.
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mode area scaling with all solid Photonic Bandgap fibers
Optics Express, 2012Co-Authors: Fanting Kong, Devon Mcclane, Guancheng Gu, Thomas Hawkins, Kunimasa Saitoh, Liang DongAbstract:There are still very strong interests for power scaling in high power fiber lasers for a wide range of applications in medical, industry, defense and science. In many of these lasers, fiber nonlinearities are the main limits to further scaling. Although numerous specific techniques have studied for the suppression of a wide range of nonlinearities, the fundamental solution is to scale mode areas in fibers while maintaining sufficient single mode operation. Here the key problem is that more modes are supported once physical dimensions of waveguides are increased. The key to solve this problem is to look for fiber designs with significant higher order mode suppression. In conventional waveguides, all modes are increasingly guided in the center of the waveguides when waveguide dimensions are increased. It is hard to couple a mode out in order to suppress its propagation, which severely limits their scalability. In an all-solid Photonic Bandgap fiber, modes are only guided due to anti-resonance of cladding Photonic crystal lattice. This provides strongly mode-dependent guidance, leading to very high differential mode losses. In addition, the all-solid nature of the fiber makes it easily spliced to other fibers. In this paper, we will show for the first time that all-solid Photonic Bandgap fibers with effective mode area of ~920μm2 can be made with excellent higher order mode suppression.
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design principle for realizing low bending losses in all solid Photonic Bandgap fibers
Journal of Lightwave Technology, 2011Co-Authors: Tadashi Murao, Koyuru Nagao, Kunimasa Saitoh, Masanori KoshibaAbstract:In this paper, the structural dependence of factor which mainly affects a bending loss property is theoretically investigated in all-solid Photonic Bandgap fibers (PBGFs). A design principle for realizing low bending losses is successfully figured out for the first-order Photonic Bandgap (PBG). In particular, one of the origins which causes the variation of bending loss property for each structural parameter is identified. In addition, we show that exploitation of a large pitch relative to a rod diameter, aiming to realize a large-mode area (LMA) structure, leads to a significant degradation of the bending loss property. Moreover, it is demonstrated that a V-value which is proposed for all-solid PBGFs is also reduced significantly for the LMA condition. The origin of the degradation is attributed to the newly-excited Bloch state which determines the second-order PBG edge.
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bend insensitive and effectively single moded all solid Photonic Bandgap fibers with heterostructured cladding
European Conference on Optical Communication, 2009Co-Authors: Tadashi Murao, Kuniaki Maeda, Toshiki Taru, Takuji Nagashima, Kunimasa Saitoh, Takashi Sasaki, Masanori KoshibaAbstract:We propose a novel concept of cladding structure in all-solid Photonic Bandgap fibers. It promises low bending and confinement losses with single-mode operation. The mechanism is based on the new concept of heterostructured cladding.
D J Richardson - One of the best experts on this subject based on the ideXlab platform.
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microbending effects in hollow core Photonic Bandgap fibers
2016Co-Authors: Eric Numkam Fokoua, D J Richardson, Yong Chen, Flavio PolettiAbstract:We developed a model for the study of how microbends affect the operation of hollow-core Photonic Bandgap fibers. Increased loss due to intermodal coupling is predicted. Preliminary experimental observations are in good agreement with the model’s predictions.
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accurate modelling of hollow core Photonic Bandgap fibre
Advanced Photonics (2014) paper SoM4B.4, 2014Co-Authors: Numkam E Fokoua, N K Baddela, Seyed Reza Sandoghchi, J.r. Hayes, D J Richardson, Yong Chen, N V Wheeler, M N Petrovich, Francesco PolettiAbstract:A modelling tool to accurately reproduce the performance of fabricated hollow-core Photonic Bandgap fibers from their SEM images is presented. This enables new understanding of the effect of cross-sectional distortions.
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low loss tightly coilable hollow core Photonic Bandgap fibers for mid ir applications
Photonics Society Summer Topical Meeting Series, 2014Co-Authors: N V Wheeler, N K Baddela, Eric Numkam Fokoua, Seyed Reza Sandoghchi, Flavio Poletti, J.r. Hayes, M N Petrovich, Alexander M Heidt, D J RichardsonAbstract:We describe low loss (50dB/km at 3.3µm) and low bend sensitivity mid-IR hollow core-Photonic Bandgap fiber. Gas sensing applications are highlighted by a methane spectrum recorded in our fiber.
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accurate loss and surface mode modeling in fabricated hollow core Photonic Bandgap fibers
Optical Fiber Communication Conference, 2014Co-Authors: Eric Numkam Fokoua, Natalie V. Wheeler, N K Baddela, Seyed Reza Sandoghchi, J.r. Hayes, D J Richardson, Marco N. Petrovich, Yong Chen, Flavio PolettiAbstract:We present a method to reconstruct the cross-sectional profile of fabricated hollow-core Photonic Bandgap fibers from SEM images. For the first time, numerical simulations show a good agreement with measured loss and surface mode position.
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development of low loss wide bandwidth hollow core Photonic Bandgap fibers
Optical Fiber Communication Conference, 2013Co-Authors: Marco N. Petrovich, Natalie V. Wheeler, N K Baddela, E Numkam, D R Gray, Radan Slavik, Flavio Poletti, John Peter F Wooler, J.r. Hayes, D J RichardsonAbstract:We present a detailed overview of progress in the development of hollow-core Photonic Bandgap fibers with improved transmission and modal properties which demonstrates the feasibility and potential of this fiber solution for future telecom systems.
Araceli Bjarklev - One of the best experts on this subject based on the ideXlab platform.
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167 w power scalable ytterbium doped Photonic Bandgap fiber amplifier at 1178nm
Optics Express, 2010Co-Authors: Christina B Olausson, Araceli Bjarklev, Jes Broeng, Akira Shirakawa, Meishin Chen, Jens K Lyngso, K P Hansen, Kenichi UedaAbstract:An ytterbium-doped Photonic Bandgap fiber amplifier operating at the long wavelength edge of the ytterbium gain band is investigated for high power amplification. The spectral filtering effect of the Photonic Bandgap efficiently suppresses amplified spontaneous emission at the conventional ytterbium gain wavelengths and thus enables high power amplification at 1178 nm. A record output power of 167 W, a slope efficiency of 61% and 15 dB saturated gain at 1178 nm have been demonstrated using the ytterbium-doped Photonic Bandgap fiber.
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Electrically controlled broadband liquid crystal Photonic Bandgap fiber polarimeter
Optics Letters, 2007Co-Authors: Thomas Tanggaard Alkeskjold, Araceli BjarklevAbstract:We demonstrate a liquid crystal Photonic Bandgap fiber based polarizer integrated in a double silicon v-groove assembly. The polarizer axis can be electrically controlled as well as switched on and off.
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gas sensing using air guiding Photonic Bandgap fibers
Conference on Lasers and Electro-Optics, 2004Co-Authors: Tuomo Ritari, Araceli Bjarklev, Thorkild Sorensen, Hanne Ludvigsen, J C Petersen, T.p. HansenAbstract:We report on experimental studies of gas sensing using air-guiding Photonic Bandgap fibers. The Photonic Bandgap fibers have at one end been spliced to standard single mode fibers for ease of use and improved stability
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mode areas and field energy distribution in honeycomb Photonic Bandgap fibers
Journal of The Optical Society of America B-optical Physics, 2003Co-Authors: Jesper Laegsgaard, Niels Asger Mortensen, Araceli BjarklevAbstract:The field-energy distributions and effective mode areas of silica-based Photonic Bandgap fibers with a honeycomb air-hole structure in the cladding and an extra air hole defining the core are investigated. We present a generalization of the common effective-area definition, suitable for the problem at hand, and compare the results for the Photonic Bandgap fibers with those of index-guiding microstructured fibers. While the majority of the field energy in the honeycomb Photonic Bandgap fibers is found to reside in the silica, a substantial fraction (up to ∼30%) can be located in the air holes. This property may show such fibers as particularly interesting for sensor applications, especially those based on nonlinear effects or interaction with other structures (e.g., Bragg gratings) in the glass.
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material effects in air guiding Photonic Bandgap fibers
Journal of The Optical Society of America B-optical Physics, 2003Co-Authors: Jesper Laegsgaard, Niels Asger Mortensen, Jesper Riishede, Araceli BjarklevAbstract:The waveguiding properties of two silica-based, air-guiding Photonic Bandgap fiber designs are investigated with special emphasis on material effects. The nonlinear coefficients are found to be 1–2 orders of magnitude smaller than those obtained in index-guiding microstructured fibers with large mode areas. The material dispersion of silica makes a significant contribution to the total chromatic dispersion even though less than 10% of the field energy is located in the silica regions of the fibers. These findings suggest that dispersion engineering through the choice of base material may be a possibility in this type of fiber.
Masanori Koshiba - One of the best experts on this subject based on the ideXlab platform.
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design principle for realizing low bending losses in all solid Photonic Bandgap fibers
Journal of Lightwave Technology, 2011Co-Authors: Tadashi Murao, Koyuru Nagao, Kunimasa Saitoh, Masanori KoshibaAbstract:In this paper, the structural dependence of factor which mainly affects a bending loss property is theoretically investigated in all-solid Photonic Bandgap fibers (PBGFs). A design principle for realizing low bending losses is successfully figured out for the first-order Photonic Bandgap (PBG). In particular, one of the origins which causes the variation of bending loss property for each structural parameter is identified. In addition, we show that exploitation of a large pitch relative to a rod diameter, aiming to realize a large-mode area (LMA) structure, leads to a significant degradation of the bending loss property. Moreover, it is demonstrated that a V-value which is proposed for all-solid PBGFs is also reduced significantly for the LMA condition. The origin of the degradation is attributed to the newly-excited Bloch state which determines the second-order PBG edge.
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bend insensitive and effectively single moded all solid Photonic Bandgap fibers with heterostructured cladding
European Conference on Optical Communication, 2009Co-Authors: Tadashi Murao, Kuniaki Maeda, Toshiki Taru, Takuji Nagashima, Kunimasa Saitoh, Takashi Sasaki, Masanori KoshibaAbstract:We propose a novel concept of cladding structure in all-solid Photonic Bandgap fibers. It promises low bending and confinement losses with single-mode operation. The mechanism is based on the new concept of heterostructured cladding.
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detailed theoretical investigation of bending properties in solid core Photonic Bandgap fibers
Optics Express, 2009Co-Authors: Tadashi Murao, Kunimasa Saitoh, Masanori KoshibaAbstract:In this paper, detailed properties of bent solid-core Photonic Bandgap fibers (SC-PBGFs) are investigated. We propose an approximate equivalent straight waveguide (ESW) formulation for Photonic Bandgap (PBG) edges, which is convenient to see qualitatively which radiation (centripetal or centrifugal radiation) mainly occurs and the impact of bend losses for an operating wavelength. In particular, we show that cladding modes induced by bending cause several complete or incomplete leaky mode couplings with the core mode and the resultant loss peaks. Moreover, we show that the field distributions of the cladding modes are characterized by three distinct types for blue-edge, mid-gap, and red-edge wavelengths in the PBG, which is explained by considering the cladding Bloch states or resonant conditions without bending. Next, we investigate the structural dependence of the bend losses. In particular, we demonstrate the bend-loss dependence on the number of the cladding rings. Finally, by investigating the impacts of the order of PBG and the core structure on the bend losses, we discuss a tight-bending structure.
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reversed dispersion slope Photonic Bandgap fibers for broadband dispersion control in femtosecond fiber lasers
Optics Express, 2008Co-Authors: Z Varallyay, J. Fekete, Kuniaki Kakihara, Masanori Koshiba, Kunimasa Saitoh, R. SzipocsAbstract:Higher-order-mode solid and hollow core Photonic Bandgap fibers exhibiting reversed or zero dispersion slope over tens or hundreds of nanometer bandwidths within the Bandgap are presented. This attractive feature makes them well suited for broadband dispersion control in femtosecond pulse fiber lasers, amplifiers and optical parametric oscillators. The canonical form of the dispersion profile in Photonic Bandgap fibers is modified by a partial reflector layer/interface placed around the core forming a 2D cylindrical Gires-Tournois type interferometer. This small perturbation in the index profile induces a frequency dependent electric field distribution of the preferred propagating higher-order-mode resulting in a zero or reversed dispersion slope.
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high group birefringence in air core Photonic Bandgap fibers
Optics Letters, 2005Co-Authors: Shah M Alam, Kunimasa Saitoh, Masanori KoshibaAbstract:A numerical investigation of group birefringence is carried out on a recently reported highly birefringent hollow-core Photonic Bandgap fiber by use of an efficient vector finite-element method. The hollow fiber core has an area as large as that of approximately four airholes in the cladding region and assumes a rhombic shape with round corners, and the airholes in the cladding region are hexagonal and provide a high air-filling fraction. Numerical results show very high group birefringence of the order of 10?2 and phase birefringence of the order of 10?3.
