Large Mode Area Fibers for High Power Applications

Broderick, Neil G. R.; Offerhaus, Herman L.; Richardson, David J.; Sammut, R.A.; Caplen, J.E.; Dong, Liang

doi:10.1006/ofte.1998.0292

Cited by 127 publications

(57 citation statements)

References 10 publications

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“…We have recently reported a Q-switched fiber laser capable of generating 2.3-mJ pulses in a cladding-pumped configuration [3] based on LMA fiber. The core area, in this case, was 1300 m , more than a factor of 50 greater than that in standard Yb-doped single-mode fibers [5]. We have also reported CW laser operation of multimode fibers with a tapered section for suppression of higher order modes [6].…”

Section: Introductionmentioning

confidence: 70%

Characteristics of Q-switched cladding-pumped ytterbium-doped fiber lasers with different high-energy fiber designs

Ranaud

Offerhaus

Álvarez-Chávez

et al. 2001

IEEE J. Quantum Electron.

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130

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Abstract-We theoretically and experimentally analyze Q-switched cladding pumped ytterbium-doped fiber lasers designed for high pulse energies. We compare the extractable energy from two high-energy fiber designs: 1) single-or few-moded low-NA large mode area (LMA) fibers and 2) large-core multimode fibers, which may incorporate a fiber taper for brightness enhancement. Our results show that the pulse energy is proportional to the effective core area and, therefore, LMA fibers and multimode fibers of comparable core size give comparable results. However, the energy storage in multimode fibers is mostly limited by strong losses due to amplified spontaneous emission (ASE) or even spurious lasing between pulses. The ASE power increases with the number of modes in a fiber. Furthermore, spurious feedback is more difficult to suppress with a higher NA, and Rayleigh back-scattering increases with higher NA, too. These effects are smaller in low-NA LMA fibers, allowing for somewhat higher energy storage. For the LMA fibers, we found that facet damage was a more severe restriction than ASE losses or spurious lasing. With a modified laser cavity, we could avoid facet damage in the LMA fiber, and reached output pulse energies as high as 2.3 mJ, limited by ASE. Theoretical estimates suggest that output pulse energies around 10 mJ are feasible with a larger core fiber, while maintaining a good beam quality.Index Terms-Double-cladding, fiber laser, large core fiber, Q-switched laser, Ytterbium.

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Section: Introductionmentioning

confidence: 70%

Characteristics of Q-switched cladding-pumped ytterbium-doped fiber lasers with different high-energy fiber designs

Ranaud

Offerhaus

Álvarez-Chávez

et al. 2001

IEEE J. Quantum Electron.

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130

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“…Furthermore, both Nd 3+ and Yb 3+ emit in the wavelength range of ∼ 1 µm, and thus the output power from claddingpumped Nd 3+ -Yb 3+ codoped fiber lasers (NYDFL) can be scaled to hundreds of watts [6], [7]. In order to achieve such high output powers without reaching the threshold of nonlinear effects, the dimensions of the fiber core must be increased and the fiber becomes intrinsically multimode [8]. Bending losses can be applied to discriminate the fundamental LP 01 mode from higher order modes so that the laser output becomes practically single mode [9].…”

Section: +mentioning

confidence: 99%

“…We note that the Nd 3+ transitions 4 F 3/2 -4 I 13/2 at ∼ 1300 nm can also contribute to the ASE power, but we found that this contribution is small for the range of parameters assumed in this work, and therefore, it was neglected. The rate of change of the ASE spectral power densities and the pump power along the fiber length are given below by (8) and (9). Here, dP…”

Section: Theoretical Modelmentioning

confidence: 99%

“…For simplicity, we assume that the scattering losses are constant. Nonlinear effects are not included in (8) and (9), shown at the bottom of the page, as recent experiments have shown that they are relatively weak for the range of pumping powers and fiber geometries that are assumed in this work [7]. In this work, we focus only on the steady-state solutions (i.e., ∂/∂t ≡ 0) to the coupled rate-propagation equations (2)- (4), (8), and (9).…”

Section: Theoretical Modelmentioning

confidence: 99%

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Modeling and optimization of high-power Nd/sup 3+/-Yb/sup 3+/ codoped fiber lasers

Yahel

Hess

Hardy

2006

J. Lightwave Technol.

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“…The key technology in this progress is the development of larger mode field area fibers (especially very large mode field area (VLMA) fibers with mode-field diameters (MFDs) beyond 50 µm) which is an effective way to increase the storage energy and mitigate intensity-related nonlinear effects [3] .…”

Section: Introductionmentioning

confidence: 99%

Review of fiber superluminescent pulse amplifications

Zhang

Shen

et al. 2016

High Pow Laser Sci Eng

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High coherence of the laser is indispensable light sources in modern long or short-distance imaging systems, because the high coherence leads to coherent artifacts such as speckle that corrupt image formation. To deliver low coherence pulses in fiber amplifiers, we utilize the superluminescent pulsed light with broad bandwidth, nonlongitudinal mode structure and chaotic mode phase as the seed source of the cascaded fiber amplifiers. The influence of fiber superluminescent pulse amplification (SPA) on the limitations of the performance is analyzed. A review of our research results for SPA in the fibers are present, including the nonlinear theories of this low coherent light sources, i.e., self-focusing (SF), stimulated Raman scattering (SRS) and self-phase modulation (SPM) effects, and the experiment results of the nanosecond pulses with peak power as high as 4.8 MW and pulse energy as much as 55 mJ. To improve the brightness of SPA light in the future work, we introduce our novel evaluation term and a more reasonable criterion, which is denoted by a new parameter of brightness factor for active large mode area fiber designs. A core-doped active large pitch fiber with a core diameter of 190 µm and a mode-field diameter of 180 µm is designed by this method. The designed fiber allows near diffracted limited beam quality operation, and it can achieve 100 mJ pulse energy and 540 W average power by analyzing the mode coupling effects induced by heat.

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Large Mode Area Fibers for High Power Applications

Cited by 127 publications

References 10 publications

Characteristics of Q-switched cladding-pumped ytterbium-doped fiber lasers with different high-energy fiber designs

Characteristics of Q-switched cladding-pumped ytterbium-doped fiber lasers with different high-energy fiber designs

Modeling and optimization of high-power Nd/sup 3+/-Yb/sup 3+/ codoped fiber lasers

Review of fiber superluminescent pulse amplifications

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