The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
G.p. Agrawal - One of the best experts on this subject based on the ideXlab platform.
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Purely phase-sampled fiber Bragg Gratings for broadband dispersion and dispersion slope compensation based on the coupling coefficient chirp
2005 Quantum Electronics and Laser Science Conference, 2005Co-Authors: G.p. AgrawalAbstract:We propose a purely phase-sampled Bragg Grating for dispersion and dispersion slope compensation by introducing a chirp in the Grating Period and coupling coefficient. The bandwidth of all reflected channels can be equalized by chirping the sampling Period and the coupling coefficient at the same time.
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bandwidth equalization of purely phase sampled fiber bragg Gratings for broadband dispersion and dispersion slope compensation
Optics Express, 2004Co-Authors: G.p. AgrawalAbstract:We propose a purely phase-sampled Bragg Grating for dispersion and dispersion slope compensation by introducing a chirp in the Grating Period and coupling coefficient. The bandwidth of all reflected channels can be equalized by chirping the sampling Period at the same time. We show that a trade-off exists between the linearity of dispersion slope and the equalization of reflection channel bandwidths and discuss how the values of the coupling coefficients can be optimized in practice to improve the device performance.
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add drop multiplexers and interleavers with broad band chromatic dispersion compensation based on purely phase sampled fiber Gratings
IEEE Photonics Technology Letters, 2004Co-Authors: G.p. AgrawalAbstract:We propose an add-drop multiplexer (ADM), designed using a purely phase-sampled superstructure fiber Bragg Grating and capable of compensating accumulated link dispersion over a wide bandwidth. Both the Grating Period and the sampling Period are chirped linearly along the length of Grating for realizing broad-band compensation. We also discuss how such Gratings can be used to design a multichannel ADMs and channel interleavers while compensating the dispersion for all reflected channels.
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Purely phase-sampled fiber Bragg Gratings for broad-band dispersion and dispersion slope compensation
IEEE Photonics Technology Letters, 2003Co-Authors: G.p. AgrawalAbstract:We demonstrated numerically that both the chromatic dispersion and the dispersion slope can be compensated by using purely phase-sampled superstructure fiber Bragg Gratings provided both the Grating Period and the sampling Period are chirped linearly along the Grating. Adjusting the refractive index modulation and the chirp of sampling function, they can be designed to compensate dispersion of a large number of wavelength-division-multiplexing channels.
Stefan Nolte - One of the best experts on this subject based on the ideXlab platform.
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variable wavefront tuning with a slm for tailored femtosecond fiber bragg Grating inscription
Optics Letters, 2016Co-Authors: Christian Voigtlander, Daniel Richter, Ria G Kramer, Thorsten A Goebel, Stefan NolteAbstract:We report on the inscription of fiber Bragg Gratings using femtosecond laser pulses and the phase-mask technique. The wavefront of the inscription laser is variably tuned with a spatial light modulator (SLM). By applying Fresnel lenses with different focal lengths, the Period of the fiber Bragg Gratings could be shifted. A linear change of the Grating Period for a FBG inscribed with a third-order deformed wavefront and a quadratic-Period behavior for a fourth-order wavefront could be verified experimentally for the first time.
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femtosecond direct writing of low loss fiber bragg Gratings using a continuous core scanning technique
Optics Letters, 2013Co-Authors: Robert J Williams, Stefan Nolte, Ria G Kramer, Michael J WithfordAbstract:We report the inscription of low-loss fiber Bragg Gratings using focused femtosecond (fs) pulses and a continuous core-scanning technique. This direct-write technique produces high-fidelity Type I-IR Gratings that share the inherent advantages of other direct-write methods, such as the point-by-point (PbP) method, for which the Grating Period is a free parameter. However, here we demonstrate an order of magnitude improvement in scattering loss compared to PbP Gratings, to a level comparable with that of phase-mask-based fs inscription. A first-order Grating was inscribed in standard telecommunications fiber with −49 dB transmission at the Bragg wavelength and 0.1 dB broadband scattering loss. Potential application of these Gratings to large-mode-area fibers and chirped Grating fabrication are highlighted.
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ultrashort pulse inscription of tailored fiber bragg Gratings with a phase mask and a deformed wavefront invited
Optical Materials Express, 2011Co-Authors: Christian Voigtlander, Andreas Tünnermann, Ria G Becker, Jens Thomas, Daniel Richter, Anshuman Singh, Stefan NolteAbstract:We report on the inscription of chirped fiber Bragg Gratings (FBGs) with a phase mask and a deformed wavefront using a femtosecond laser. A qualitative model is developed to predict the behavior of the resulting Grating Period for a deformed wavefront. In addition the quantitative change of the Period was simulated based on a ray optical solution of the diffraction behind the phase mask. For deforming the wavefront experimentally a cylindrical tuning lens was used. Tilting of the lens increased the higher order aberrations like coma and spherical aberration, which leads to chirped FBGs. A chirped FBG with a FWHM bandwidth of 2.5 nm could be realized. The change of the resulting fiber Bragg Grating Period was measured using a side diffraction setup yielding good agreement with the measured spectra.
Chinlon Lin - One of the best experts on this subject based on the ideXlab platform.
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spectral response of long Period fiber Grating based on tapered fiber with side contacted metal Grating
Journal of Lightwave Technology, 2010Co-Authors: Kueichu Hsu, Cheng-ling Lee, Yinchieh Lai, Nankuang Chen, Yusyun Chih, Peijhen Jhuang, Chinlon LinAbstract:A new long-Period fiber Grating structure based on a tapered fiber side contacted with a metal Grating is proposed and demonstrated in this paper. The temperature/index tuning sensitivity can be enhanced, and the unusual spectral response of decreasing phase-matching wavelength with respect to increasing Grating Period and temperature is observed.
Andreas Tünnermann - One of the best experts on this subject based on the ideXlab platform.
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ultrashort pulse inscription of tailored fiber bragg Gratings with a phase mask and a deformed wavefront invited
Optical Materials Express, 2011Co-Authors: Christian Voigtlander, Andreas Tünnermann, Ria G Becker, Jens Thomas, Daniel Richter, Anshuman Singh, Stefan NolteAbstract:We report on the inscription of chirped fiber Bragg Gratings (FBGs) with a phase mask and a deformed wavefront using a femtosecond laser. A qualitative model is developed to predict the behavior of the resulting Grating Period for a deformed wavefront. In addition the quantitative change of the Period was simulated based on a ray optical solution of the diffraction behind the phase mask. For deforming the wavefront experimentally a cylindrical tuning lens was used. Tilting of the lens increased the higher order aberrations like coma and spherical aberration, which leads to chirped FBGs. A chirped FBG with a FWHM bandwidth of 2.5 nm could be realized. The change of the resulting fiber Bragg Grating Period was measured using a side diffraction setup yielding good agreement with the measured spectra.
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multilevel blazed Gratings in resonance domain an alternative to the classical fabrication approach
Optics Express, 2011Co-Authors: Maria Oliva, Torsten Harzendorf, Dirk Michaelis, Uwe D Zeitner, Andreas TünnermannAbstract:In this paper we present a novel technological approach for the fabrication of multilevel Gratings in the resonance domain. A coded chromium mask is used to avoid alignment errors in electron beam lithography, which typically occur within the standard multistep binary micro-optics technology. The lateral features of all phase levels of the Grating are encoded in a single chromium mask. The final profile of the structure is obtained by selective etching process for each level. This new technological method is applied for the fabrication of two different three-level Gratings in resonance domain. The corresponding optical response as well as structural characterizations are presented and discussed. In particular, a first order diffraction efficiency of 90% is demonstrated for a Grating Period twice the wavelength at normal incidence.
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broadband iridium wire grid polarizer for uv applications
Optics Letters, 2011Co-Authors: Thomas Weber, Thomas Käsebier, Ernst-bernhard Kley, Andreas TünnermannAbstract:In this Letter, we present an iridium wire grid polarizer with a large spectral working range from IR down to the UV spectral region. The required Grating Period of 100nm for an application below a wavelength of 300nm was realized using a spatial frequency doubling technique based on ultrafast electron beam writing. The optical performance of the polarizer at a wavelength of 300nm is a transmittance of almost 60% and an extinction ratio of about 30 (15dB). Furthermore, the oxidation resistance is discussed.
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highly efficient transmission Gratings in fused silica for chirped pulse amplification systems
Applied Optics, 2003Co-Authors: Tina Clausnitzer, Andreas Tünnermann, Ernst-bernhard Kley, Jens Limpert, Karsten Zollner, H Zellmer, Hansjoerg Fuchs, Marco Jupe, Detlev RistauAbstract:We report on highly efficient transmission Gratings in fused silica with a Grating Period of 800 nm generated by electron-beam lithography. At a wavelength of 1060 nm, 95% diffraction efficiency is achieved under Littrow conditions. The damage threshold, extremely enhanced compared with conventional gold-coated diffraction Gratings, makes these Gratings the key elements in high average power (>100 W) femtosecond fiber chirped-pulse amplification systems.
F Bucholtz - One of the best experts on this subject based on the ideXlab platform.
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analysis of the response of long Period fiber Gratings to external index of refraction
Journal of Lightwave Technology, 1998Co-Authors: Heather Patrick, Alan D Kersey, F BucholtzAbstract:This paper demonstrates that the change in wavelength of a long Period fiber Grating attenuation band with changes in external index of refraction can be enhanced by proper selection of the Grating Period. We calculate and experimentally verify that the wavelength shift caused by changing the external index from n=1 to n=1.44 of the attenuation band which appears in the 1400-1600 nm region in a 200-/spl mu/m Period Grating is four times that in a 350-/spl mu/m Period Grating. Changes in the spectrum over a wavelength range from 1100 to 1600 nm and 1
