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Andreas Tunnermann - One of the best experts on this subject based on the ideXlab platform.

  • single mode propagation with 205µm mode Field Diameter in a passive large pitch fiber
    Fiber Lasers XVI: Technology and Systems, 2019
    Co-Authors: Albrecht Steinkopff, Fabian Stutzki, Cesar Jauregui, Andreas Tunnermann, Johannes Nold, Christian Hupel, Nicoletta Haarlammert, Joerg Bierlich, Jens Limpert
    Abstract:

    We present theoretical and experimental investigations on effective single-transverse mode propagation in very large mode area (VLMA) fibers. Upscaling the mode area of fibers is the most effective approach to reduce the nonlinear interaction and, therefore, to allow for the confinement of high-power radiation without detrimental nonlinear effects. Even though the investigations are carried out in a passive large pitch fiber (LPF), they reveal an intrinsic scaling potential of this design which, if unlocked, will be beneficial for active VLMA fibers in the future. A commercial mode solver based on a full-vectorial finite-difference approach has been used to simulate the confinement losses of the fundamental and higher-order transverse modes. These simulations have revealed that the differential loss in one-missing-hole photonic crystal fibers can be tailored to be larger than 10 dB/m for fiber core sizes larger than 200 μm at 1 μm wavelength. In order to test the theoretical predictions experimental investigations have been performed. Therefore, a rod-type fiber has been fabricated and effective single-mode operation with unprecedented large mode-Field Diameters has been demonstrated. We were able to achieve single-mode propagation in a passive 1.3 m long LPF with a pitch of 140 μm possessing a mode-Field Diameter of 205 μm. Even a strong misalignment of the coupling condition did not lead to any significant appearance of higher order modes at the fiber exit, which proves the robustness of the singlemode operation. To the best of our knowledge these results represent the largest dimension of a fundamental transverse mode reported in a waveguide structure at 1 μm wavelength to date. Compared to previous results the mode area is scaled by a factor of about 4 (with respect to active fibers) and a factor of ~8 (with respect to passive fibers).

  • transverse single mode operation in a passive large pitch fiber with more than 200 μm mode Field Diameter
    Optics Letters, 2019
    Co-Authors: Albrecht Steinkopff, Fabian Stutzki, Cesar Jauregui, Andreas Tunnermann, Johannes Nold, Christian Hupel, Nicoletta Haarlammert, Joerg Bierlich, Jens Limpert
    Abstract:

    In this Letter, we present, to the best of our knowledge, the largest effective single-mode fiber reported to date. The employed waveguide is a passive large pitch fiber (LPF), which shows the core area scaling potential of such a fiber structure. In particular, we achieved stable single-transverse mode transmission at a wavelength of 1.03 μm through a straight passive LPF with a pitch of 140 μm, resulting in a measured mode-Field Diameter of 205 μm.

  • tm based fiber laser system with more than 200 mw peak power
    Optics Letters, 2015
    Co-Authors: Fabian Stutzki, Jens Limpert, Florian Jansen, Cesar Jauregui, Christian Gaida, Martin Gebhardt, Andreas Tunnermann
    Abstract:

    Tm-based fiber-laser systems are an attractive concept for the development of high-performance laser sources in the spectral region around 2 μm wavelength. Here we present a system delivering a pulse-peak power higher than 200 MW in combination with 24 W average power and 120 μJ pulse energy. Key components enabling this performance level are a Tm-doped large-pitch fiber with a mode-Field Diameter of 65 μm, highly efficient dielectric gratings, and a Tm-based fiber oscillator operating in the stretched-pulse regime.

  • yb doped large pitch fiber with 105 µm mode Field Diameter
    Optical Fiber Communication Conference, 2011
    Co-Authors: Florian Jansen, Jens Limpert, Fabian Stutzki, Tino Eidam, Jan Rothhardt, Steffen Hadrich, Henning Carstens, Cesar Jauregui, Andreas Tunnermann
    Abstract:

    We present an active Yb-doped Large Pitch Fiber design with 105 µm mode Field Diameter. The fiber was tested in a fiber CPA system delivering sub 500 fs, 2 mJ pulses with 3.8 GW peak power. The limiting influence of anticrossings on beam quality and average output power is discussed.

  • high average power large pitch fiber amplifier with robust single mode operation
    Optics Letters, 2011
    Co-Authors: Fabian Stutzki, Jens Limpert, Florian Jansen, Tino Eidam, Cesar Jauregui, Alexander Steinmetz, Andreas Tunnermann
    Abstract:

    Ytterbium-doped large-pitch fibers with very large mode areas are investigated in a high-power fiber amplifier configuration. An average output power of 294 W is demonstrated, while maintaining robust single-mode operation with a mode Field Diameter of 62 μm. Compared to previous active large-mode area designs, the threshold of mode instabilities is increased by a factor of about 3.

Jens Limpert - One of the best experts on this subject based on the ideXlab platform.

  • single mode propagation with 205µm mode Field Diameter in a passive large pitch fiber
    Fiber Lasers XVI: Technology and Systems, 2019
    Co-Authors: Albrecht Steinkopff, Fabian Stutzki, Cesar Jauregui, Andreas Tunnermann, Johannes Nold, Christian Hupel, Nicoletta Haarlammert, Joerg Bierlich, Jens Limpert
    Abstract:

    We present theoretical and experimental investigations on effective single-transverse mode propagation in very large mode area (VLMA) fibers. Upscaling the mode area of fibers is the most effective approach to reduce the nonlinear interaction and, therefore, to allow for the confinement of high-power radiation without detrimental nonlinear effects. Even though the investigations are carried out in a passive large pitch fiber (LPF), they reveal an intrinsic scaling potential of this design which, if unlocked, will be beneficial for active VLMA fibers in the future. A commercial mode solver based on a full-vectorial finite-difference approach has been used to simulate the confinement losses of the fundamental and higher-order transverse modes. These simulations have revealed that the differential loss in one-missing-hole photonic crystal fibers can be tailored to be larger than 10 dB/m for fiber core sizes larger than 200 μm at 1 μm wavelength. In order to test the theoretical predictions experimental investigations have been performed. Therefore, a rod-type fiber has been fabricated and effective single-mode operation with unprecedented large mode-Field Diameters has been demonstrated. We were able to achieve single-mode propagation in a passive 1.3 m long LPF with a pitch of 140 μm possessing a mode-Field Diameter of 205 μm. Even a strong misalignment of the coupling condition did not lead to any significant appearance of higher order modes at the fiber exit, which proves the robustness of the singlemode operation. To the best of our knowledge these results represent the largest dimension of a fundamental transverse mode reported in a waveguide structure at 1 μm wavelength to date. Compared to previous results the mode area is scaled by a factor of about 4 (with respect to active fibers) and a factor of ~8 (with respect to passive fibers).

  • transverse single mode operation in a passive large pitch fiber with more than 200 μm mode Field Diameter
    Optics Letters, 2019
    Co-Authors: Albrecht Steinkopff, Fabian Stutzki, Cesar Jauregui, Andreas Tunnermann, Johannes Nold, Christian Hupel, Nicoletta Haarlammert, Joerg Bierlich, Jens Limpert
    Abstract:

    In this Letter, we present, to the best of our knowledge, the largest effective single-mode fiber reported to date. The employed waveguide is a passive large pitch fiber (LPF), which shows the core area scaling potential of such a fiber structure. In particular, we achieved stable single-transverse mode transmission at a wavelength of 1.03 μm through a straight passive LPF with a pitch of 140 μm, resulting in a measured mode-Field Diameter of 205 μm.

  • tm based fiber laser system with more than 200 mw peak power
    Optics Letters, 2015
    Co-Authors: Fabian Stutzki, Jens Limpert, Florian Jansen, Cesar Jauregui, Christian Gaida, Martin Gebhardt, Andreas Tunnermann
    Abstract:

    Tm-based fiber-laser systems are an attractive concept for the development of high-performance laser sources in the spectral region around 2 μm wavelength. Here we present a system delivering a pulse-peak power higher than 200 MW in combination with 24 W average power and 120 μJ pulse energy. Key components enabling this performance level are a Tm-doped large-pitch fiber with a mode-Field Diameter of 65 μm, highly efficient dielectric gratings, and a Tm-based fiber oscillator operating in the stretched-pulse regime.

  • yb doped large pitch fiber with 105 µm mode Field Diameter
    Optical Fiber Communication Conference, 2011
    Co-Authors: Florian Jansen, Jens Limpert, Fabian Stutzki, Tino Eidam, Jan Rothhardt, Steffen Hadrich, Henning Carstens, Cesar Jauregui, Andreas Tunnermann
    Abstract:

    We present an active Yb-doped Large Pitch Fiber design with 105 µm mode Field Diameter. The fiber was tested in a fiber CPA system delivering sub 500 fs, 2 mJ pulses with 3.8 GW peak power. The limiting influence of anticrossings on beam quality and average output power is discussed.

  • high average power large pitch fiber amplifier with robust single mode operation
    Optics Letters, 2011
    Co-Authors: Fabian Stutzki, Jens Limpert, Florian Jansen, Tino Eidam, Cesar Jauregui, Alexander Steinmetz, Andreas Tunnermann
    Abstract:

    Ytterbium-doped large-pitch fibers with very large mode areas are investigated in a high-power fiber amplifier configuration. An average output power of 294 W is demonstrated, while maintaining robust single-mode operation with a mode Field Diameter of 62 μm. Compared to previous active large-mode area designs, the threshold of mode instabilities is increased by a factor of about 3.

Jes Broeng - One of the best experts on this subject based on the ideXlab platform.

  • q switching and efficient harmonic generation from a single mode lma photonic bandgap rod fiber laser
    Optics Express, 2011
    Co-Authors: Marko Laurila, Francois Salin, Julien Saby, Thomas Tanggaard Alkeskjold, Lara Scolari, Benjamin Cocquelin, Jes Broeng, Jesper Laegsgaard
    Abstract:

    We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode with a Mode-Field-Diameter (MFD) of 59μm. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm.

  • single mode ytterbium doped large mode area photonic bandgap rod fiber amplifier
    Optics Express, 2011
    Co-Authors: Thomas Tanggaard Alkeskjold, Marko Laurila, Lara Scolari, Jes Broeng
    Abstract:

    Enabling Single-Mode (SM) operation in Large-Mode-Area (LMA) fiber amplifiers and lasers is critical, since a SM output ensures high beam quality and excellent pointing stability. In this paper, we demonstrate and test a new design approach for achieving SM LMA rod fibers by using a photonic bandgap structure. The structure allows resonant coupling of higher-order modes from the core and acts as a spatially Distributed Mode Filter (DMF). With this approach, we demonstrate passive SM performance in an only ~50 cm long and straight ytterbium-doped rod fiber. The amplifier has a mode Field Diameter of ~59 µm at 1064 nm and exhibits a pump absorption of 27 dB/m at 976 nm.

  • single polarization ultra large mode area yb doped photonic crystal fiber
    Optics Express, 2008
    Co-Authors: O Schmidt, Jens Limpert, Tino Eidam, Jan Rothhardt, Andreas Tunnermann, Christian Jakobsen, F Roser, K P Hansen, Jes Broeng
    Abstract:

    We report on an ytterbium-doped single-transverse-mode rod-type photonic crystal fiber that combines the advantages of low nonlinearity and intrinsic polarization stability. The mode-Field-area of the fundamental mode is as large as 2300 µm2. An output power of up to 163 W with a degree of polarization better than 85% has been extracted from a simple fiber laser setup without any additional polarizing element within the cavity than the fiber itself. The beam quality has been characterized by a M2 value of 1.2. The single-polarization window ranges from 1030 to 1080 nm, hence possesses an excellent overlap with the gain profile of ytterbium-doped silica fibers. To the best of our knowledge this fiber design has the largest mode-Field-Diameter ever reported for polarizing or even polarization maintaining rare-earth-doped double-clad fibers.

  • large mode area erbium ytterbium doped photonic crystal fiber amplifier for high energy femtosecond pulses at 1 55 µm
    Optics Express, 2005
    Co-Authors: Akira Shirakawa, Jacob Riis Folkenberg, Jun Ota, Mitsuru Musha, Kenichi Nakagawa, Kenichi Ueda, Jes Broeng
    Abstract:

    We report a high-energy femtosecond fiber amplifier based on an air-cladded single-transverse-mode erbium-ytterbium-codoped photonic-crystal fiber with a 26-µm mode-Field-Diameter. 700-fs, 47-MHz pulses at 1557 nm were amplified and compressed to near-transform-limited 100-fs, 7.4-nJ pulses with 54-kW peak powers without chirped-pulse amplification. A linearly polarized output with an extinction ratio exceeding 42 dB was obtained by double-pass configuration. As an application, supercontinuum spanning from 1000 to 2500 nm was generated by a successive 2-m high-nonlinear fiber with a 140-mW average power.

  • low nonlinearity single transverse mode ytterbium doped photonic crystal fiber amplifier
    Optics Express, 2004
    Co-Authors: Jens Limpert, A Petersson, Jes Broeng, Andreas Tunnermann, A Liem, M Reich, Thomas Schreiber, Stefan Nolte, H Zellmer, Christian Jakobsen
    Abstract:

    We report on an air-clad large-core single-transverse-mode ytterbium-doped photonic crystal fiber with a mode-Field-Diameter of 35 µm, corresponding to a mode-Field-area of ~1000 µm2. In a first experiment this fiber is used to amplify 10-ps pulses to a peak power of 60 kW without significant spectral broadening due to self-phase modulation allowing for the frequency up-conversion of these pulses using narrow-bandwidth phase-matched nonlinear crystals.

Fabian Stutzki - One of the best experts on this subject based on the ideXlab platform.

  • single mode propagation with 205µm mode Field Diameter in a passive large pitch fiber
    Fiber Lasers XVI: Technology and Systems, 2019
    Co-Authors: Albrecht Steinkopff, Fabian Stutzki, Cesar Jauregui, Andreas Tunnermann, Johannes Nold, Christian Hupel, Nicoletta Haarlammert, Joerg Bierlich, Jens Limpert
    Abstract:

    We present theoretical and experimental investigations on effective single-transverse mode propagation in very large mode area (VLMA) fibers. Upscaling the mode area of fibers is the most effective approach to reduce the nonlinear interaction and, therefore, to allow for the confinement of high-power radiation without detrimental nonlinear effects. Even though the investigations are carried out in a passive large pitch fiber (LPF), they reveal an intrinsic scaling potential of this design which, if unlocked, will be beneficial for active VLMA fibers in the future. A commercial mode solver based on a full-vectorial finite-difference approach has been used to simulate the confinement losses of the fundamental and higher-order transverse modes. These simulations have revealed that the differential loss in one-missing-hole photonic crystal fibers can be tailored to be larger than 10 dB/m for fiber core sizes larger than 200 μm at 1 μm wavelength. In order to test the theoretical predictions experimental investigations have been performed. Therefore, a rod-type fiber has been fabricated and effective single-mode operation with unprecedented large mode-Field Diameters has been demonstrated. We were able to achieve single-mode propagation in a passive 1.3 m long LPF with a pitch of 140 μm possessing a mode-Field Diameter of 205 μm. Even a strong misalignment of the coupling condition did not lead to any significant appearance of higher order modes at the fiber exit, which proves the robustness of the singlemode operation. To the best of our knowledge these results represent the largest dimension of a fundamental transverse mode reported in a waveguide structure at 1 μm wavelength to date. Compared to previous results the mode area is scaled by a factor of about 4 (with respect to active fibers) and a factor of ~8 (with respect to passive fibers).

  • transverse single mode operation in a passive large pitch fiber with more than 200 μm mode Field Diameter
    Optics Letters, 2019
    Co-Authors: Albrecht Steinkopff, Fabian Stutzki, Cesar Jauregui, Andreas Tunnermann, Johannes Nold, Christian Hupel, Nicoletta Haarlammert, Joerg Bierlich, Jens Limpert
    Abstract:

    In this Letter, we present, to the best of our knowledge, the largest effective single-mode fiber reported to date. The employed waveguide is a passive large pitch fiber (LPF), which shows the core area scaling potential of such a fiber structure. In particular, we achieved stable single-transverse mode transmission at a wavelength of 1.03 μm through a straight passive LPF with a pitch of 140 μm, resulting in a measured mode-Field Diameter of 205 μm.

  • tm based fiber laser system with more than 200 mw peak power
    Optics Letters, 2015
    Co-Authors: Fabian Stutzki, Jens Limpert, Florian Jansen, Cesar Jauregui, Christian Gaida, Martin Gebhardt, Andreas Tunnermann
    Abstract:

    Tm-based fiber-laser systems are an attractive concept for the development of high-performance laser sources in the spectral region around 2 μm wavelength. Here we present a system delivering a pulse-peak power higher than 200 MW in combination with 24 W average power and 120 μJ pulse energy. Key components enabling this performance level are a Tm-doped large-pitch fiber with a mode-Field Diameter of 65 μm, highly efficient dielectric gratings, and a Tm-based fiber oscillator operating in the stretched-pulse regime.

  • yb doped large pitch fiber with 105 µm mode Field Diameter
    Optical Fiber Communication Conference, 2011
    Co-Authors: Florian Jansen, Jens Limpert, Fabian Stutzki, Tino Eidam, Jan Rothhardt, Steffen Hadrich, Henning Carstens, Cesar Jauregui, Andreas Tunnermann
    Abstract:

    We present an active Yb-doped Large Pitch Fiber design with 105 µm mode Field Diameter. The fiber was tested in a fiber CPA system delivering sub 500 fs, 2 mJ pulses with 3.8 GW peak power. The limiting influence of anticrossings on beam quality and average output power is discussed.

  • high average power large pitch fiber amplifier with robust single mode operation
    Optics Letters, 2011
    Co-Authors: Fabian Stutzki, Jens Limpert, Florian Jansen, Tino Eidam, Cesar Jauregui, Alexander Steinmetz, Andreas Tunnermann
    Abstract:

    Ytterbium-doped large-pitch fibers with very large mode areas are investigated in a high-power fiber amplifier configuration. An average output power of 294 W is demonstrated, while maintaining robust single-mode operation with a mode Field Diameter of 62 μm. Compared to previous active large-mode area designs, the threshold of mode instabilities is increased by a factor of about 3.

Masanori Koshiba - One of the best experts on this subject based on the ideXlab platform.

  • bending insensitive single mode hole assisted fibers with reduced splice loss
    Optics Letters, 2005
    Co-Authors: Kunimasa Saitoh, Yukihiro Tsuchida, Masanori Koshiba
    Abstract:

    We propose and demonstrate a novel type of bending-insensitive single-mode hole-assisted fiber that has a doped core and two layers of holes with two different airhole Diameters. The fiber has a 9.3 microm mode Field Diameter, a bending loss of 0.011 dB/turn at 1.55 microm for a bending Diameter of 10 mm, and a cutoff wavelength below 1.1 microm. The fiber can be fusion spliced to a conventional single-mode fiber with low loss.

  • design and characterization of single mode holey fibers with low bending losses
    Optics Express, 2005
    Co-Authors: Yukihiro Tsuchida, Kunimasa Saitoh, Masanori Koshiba
    Abstract:

    As the fiber-to-the-home network construction increased, optical fiber cables are demanded to be easier to handle and require less space. Under this situation, a single mode fiber (SMF) permitting small bending radius is strongly requested. In this paper, we propose and demonstrate a novel type of bending-insensitive single-mode holey fiber that has a doped core and two layers of holes with different air-hole Diameters. The fiber has a mode Field Diameter of 9.3 µm at 1.55 µm and a cutoff wavelength below 1.1 µm, and shows a bending loss of 0.011 dB/turn at 1.55 µm for a bending radius of 5 mm and a low splice loss of 0.08 dB per fusion-splicing to a conventional SMF.

  • applicability of classical optical fiber theories to holey fibers
    Optics Letters, 2004
    Co-Authors: Masanori Koshiba, Kunimasa Saitoh
    Abstract:

    We discuss the applicability of well-established classical optical fiber theories to holey fibers. By appropriately defining the V parameter, we can easily estimate the fundamental properties of holey fibers, such as effective index, group-velocity dispersion, mode Field Diameter, beam divergence, and splice loss, through simple empirical expressions without the need for heavy numerical computations. We confirm the validity of the V parameter defined here by comparing the calculated results with the earlier experimental and numerical results.

  • Structural dependence of effective area and mode Field Diameter for holey fibers
    Optics express, 2003
    Co-Authors: Masanori Koshiba, Kunimasa Saitoh
    Abstract:

    A rigorous full-vector finite element method is effectively applied to evaluating the effective area Aeff and the mode Field Diameter (MFD) of holey fibers (HFs) with finite cross sections. The effective modal spot size (a half of MFD), weff , is defined with the help of the second moment of the optical intensity distribution. The influence of hole Diameter, hole pitch, operating wavelength, and number of rings of air holes on Aeff and weff is investigated in detail. As a result, it is shown that Aeff and weff are almost independent of the number of hole rings and that the relation Aeff =πweff2, which is frequently utilized in the conventional optical fibers, does not always hold, especially in smaller air-filling fraction and/or longer wavelength regions. In addition, we find that for HFs with large air holes operating at longer wavelengths, the mode profiles of the two linearly polarized fundamental modes are significantly different from each other, even though they are degenerate. Using the values of Aeff and weff obtained here, the beam divergence and the nonlinear phase shift are calculated and are compared with the earlier experimental results.