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Zeng L, Ding X, Liu J, Wang X, Ye Y, Wu H, Wang P, Xi X, Zhang H, Shi C, Xi F, Xu X. Novel Bidirectional Output Ytterbium-Doped High Power Fiber Lasers: From Continuous to Quasi-Continuous. MICROMACHINES 2024; 15:153. [PMID: 38276852 DOI: 10.3390/mi15010153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
Traditional ytterbium-doped high-power fiber lasers generally use a unidirectional output structure. To reduce the cost and improve the efficiency of the fiber laser, we propose a bidirectional output fiber laser (BOFL). The BOFL has many advantages over that of the traditional unidirectional output fiber laser (UOFL) and has a wide application in the industrial field. In theory, the model of the BOFL is established, and a comparison of the nonlinear effect in the traditional UOFL and the BOFL is studied. Experimentally, high-power continuous wave (CW) and quasi-continuous wave (QCW) BOFLs are demonstrated. In the continuous laser, we first combine the BOFL with the oscillating amplifying integrated structure, and a near-single-mode bidirectional 2 × 4 kW output with a total power of above 8 kW is demonstrated. Then, with the simple BOFL, a CW bidirectional 2 × 5 kW output with a total power of above 10 kW is demonstrated. By means of pump source modulation, a QCW BOFL is developed, and the output of a near-single mode QCW laser with a peak output of 2 × 4.5 kW with a total peak power of more than 9 kW is realized. Both CW and QCW output BOFL are the highest powers reported at present.
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Affiliation(s)
- Lingfa Zeng
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Xinyi Ding
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Jiaqi Liu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Xiaolin Wang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Yun Ye
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Hanshuo Wu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Peng Wang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Xiaoming Xi
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Hanwei Zhang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Chen Shi
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Fengjie Xi
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
| | - Xiaojun Xu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
- Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
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Chen CW, Nguyen LV, Wisal K, Wei S, Warren-Smith SC, Henderson-Sapir O, Schartner EP, Ahmadi P, Ebendorff-Heidepriem H, Stone AD, Ottaway DJ, Cao H. Mitigating stimulated Brillouin scattering in multimode fibers with focused output via wavefront shaping. Nat Commun 2023; 14:7343. [PMID: 37957145 PMCID: PMC10643398 DOI: 10.1038/s41467-023-42806-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023] Open
Abstract
The key challenge for high-power delivery through optical fibers is overcoming nonlinear optical effects. To keep a smooth output beam, most techniques for mitigating optical nonlinearities are restricted to single-mode fibers. Moving out of the single-mode paradigm, we show experimentally that wavefront-shaping of coherent input light to a highly multimode fiber can increase the power threshold for stimulated Brillouin scattering (SBS) by an order of magnitude, whilst simultaneously controlling the output beam profile. The SBS suppression results from an effective broadening of the Brillouin spectrum under multimode excitation, without broadening of transmitted light. Strongest suppression is achieved with selective mode excitation that gives the broadest Brillouin spectrum. Our method is efficient, robust, and applicable to continuous waves and pulses. This work points toward a promising route for mitigating detrimental nonlinear effects in optical fibers, enabling further power scaling of high-power fiber systems for applications to directed energy, remote sensing, and gravitational-wave detection.
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Affiliation(s)
- Chun-Wei Chen
- Department of Applied Physics, Yale University, New Haven, CT, 06520, USA
| | - Linh V Nguyen
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, 5095, Australia
- Laser Physics and Photonics Devices Laboratories, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Kabish Wisal
- Department of Physics, Yale University, New Haven, CT, 06520, USA
| | - Shuen Wei
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Stephen C Warren-Smith
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, 5095, Australia.
- Laser Physics and Photonics Devices Laboratories, University of South Australia, Mawson Lakes, SA, 5095, Australia.
| | - Ori Henderson-Sapir
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
- OzGrav-Adelaide, Australian Research Council Centre of Excellence for Gravitational Wave Discovery, Adelaide, SA, 5005, Australia
| | - Erik P Schartner
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Peyman Ahmadi
- Coherent, 1280 Blue Hills Avenue, Bloomfield, CT, 06002, USA
| | - Heike Ebendorff-Heidepriem
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - A Douglas Stone
- Department of Applied Physics, Yale University, New Haven, CT, 06520, USA.
| | - David J Ottaway
- Institute for Photonics and Advanced Sensing, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
- OzGrav-Adelaide, Australian Research Council Centre of Excellence for Gravitational Wave Discovery, Adelaide, SA, 5005, Australia
| | - Hui Cao
- Department of Applied Physics, Yale University, New Haven, CT, 06520, USA.
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Chen CW, Wisal K, Eliezer Y, Stone AD, Cao H. Suppressing transverse mode instability through multimode excitation in a fiber amplifier. Proc Natl Acad Sci U S A 2023; 120:e2217735120. [PMID: 37216557 PMCID: PMC10235967 DOI: 10.1073/pnas.2217735120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
High-power fiber laser amplifiers have enabled an increasing range of applications in industry, science, and defense. The power scaling for fiber amplifiers is currently limited by transverse mode instability. Most techniques for suppressing the instability are based on single- or few-mode fibers in order to output a clean collimated beam. Here, we study theoretically using a highly multimode fiber amplifier with many-mode excitation for efficient suppression of thermo-optical nonlinearity and instability. We find that the mismatch of characteristic length scales between temperature and optical intensity variations across the fiber generically leads to weaker thermo-optical coupling between fiber modes. Consequently, the transverse mode instability (TMI) threshold power increases linearly with the number of equally excited modes. When the frequency bandwidth of a coherent seed laser is narrower than the spectral correlation width of the multimode fiber, the amplified light maintains high spatial coherence and can be transformed to any target pattern or focused to a diffraction-limited spot by a spatial mask at either the input or output end of the amplifier. Our method simultaneously achieves high average power, narrow spectral width, and good beam quality, which are required for fiber amplifiers in various applications.
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Affiliation(s)
- Chun-Wei Chen
- Department of Applied Physics, Yale University, New Haven, CT06520
| | - Kabish Wisal
- Department of Physics, Yale University, New Haven, CT06520
| | - Yaniv Eliezer
- Department of Applied Physics, Yale University, New Haven, CT06520
| | - A. Douglas Stone
- Department of Applied Physics, Yale University, New Haven, CT06520
| | - Hui Cao
- Department of Applied Physics, Yale University, New Haven, CT06520
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Dixneuf C, Guiraud G, Bardin YV, Rosa Q, Goeppner M, Hilico A, Pierre C, Boullet J, Traynor N, Santarelli G. Ultra-low intensity noise, all fiber 365 W linearly polarized single frequency laser at 1064 nm. OPTICS EXPRESS 2020; 28:10960-10969. [PMID: 32403617 DOI: 10.1364/oe.385095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/03/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate a robust linearly polarized 365 W, very low amplitude noise, single frequency master oscillator power amplifier at 1064 nm. Power scaling was done through a custom large mode area fiber with a mode field diameter of 30 µm. No evidence of stimulated Brillouin scattering or modal instabilities are observed. The relative intensity noise is reduced down to -160 dBc/Hz between 2 kHz and 10 kHz via a wide band servo loop (1 MHz bandwidth). We achieve 350 W of isolated power, with a power stability < 0.7% RMS over 1100 hours of continuous operation and a near diffraction limited beam (M2 < 1.1).
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Experimental study of the influence of mode excitation on mode instability in high power fiber amplifier. Sci Rep 2019; 9:9396. [PMID: 31253873 PMCID: PMC6598995 DOI: 10.1038/s41598-019-45787-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/10/2019] [Indexed: 11/08/2022] Open
Abstract
Mode instability with different mode excitation has been investigated by off-splicing the fusion point in a 4 kW-level monolithic fiber laser system, which reveals that the fiber systems exciting more high order mode content exhibits lower beam quality but higher mode instability threshold. The static-to-dynamic mode degradation and dynamic-only mode degradation have also been observed in the same high power fiber amplifier by varying the mode excitation, which implicates that the mode excitation plays an important role in mode characteristics in high power fiber lasers. By employing a seed with near fundamental mode beam quality, only dynamic mode degradation-mode instability sets in with negligible static beam quality degradation. Then the fusion point in the seed laser is offset spliced to excite high order mode. As the output power of the main amplifier scales, the beam quality degrades with the beam profile being static, and then the dynamic mode instability sets in, the power threshold of which is higher than that with good beam quality seed. We consider that the static mode degradation is caused by the presence of incoherent supposition of fundamental and high order mode, which leads to that the measured dynamic mode instability threshold is higher.
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Scarnera V, Ghiringhelli F, Malinowski A, Codemard CA, Durkin MK, Zervas MN. Modal instabilities in high power fiber laser oscillators. OPTICS EXPRESS 2019; 27:4386-4403. [PMID: 30876058 DOI: 10.1364/oe.27.004386] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/17/2018] [Indexed: 06/09/2023]
Abstract
Transverse mode competition and instabilities in high-power fiber oscillators have been studied experimentally by monitoring the dynamic power exchanges and characteristic frequencies of the transmitted fundamental mode (FM) and scattered high-order modes (HOMs) of the fiber laser cavity under CW and pulsed pumping. The FM and HOM power evolution indicates the presence of two competing effective laser cavities which result in rich output dynamics and full chaotic operation. The thermal and inversion related contributions to the observed instabilities have been identified by monitoring the associated characteristic instability frequencies under pulsed pumping. It is shown that in the transient regime, both inversion and thermal effects contribute successively to the observed power instabilities. Increasing the pump power leads to full chaotic response through an interplay between transverse and longitudinal mode instabilities.
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Tao R, Xiao H, Zhang H, Leng J, Wang X, Zhou P, Xu X. Dynamic characteristics of stimulated Raman scattering in high power fiber amplifiers in the presence of mode instabilities. OPTICS EXPRESS 2018; 26:25098-25110. [PMID: 30469617 DOI: 10.1364/oe.26.025098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/05/2018] [Indexed: 06/09/2023]
Abstract
Impact of mode instability on dynamic characteristics of stimulated Raman scattering in high power fiber amplifiers has been studied for the first time, which reveals another characterization of mode instability from the aspect of optical spectrum. It shows that, after the onset of mode instability, the measured light spectrums, especially the Raman light spectrums, are different from those without mode instability, which become burr-like. As mode instability evolves into different stages, the intensity of stimulated Raman scattering effects as laser power increasing also behaves differently. During the transition region, the stimulated Raman scattering effect becomes stronger as the lasing power increases until the mode instability evolves into chaotic regions, where the stimulated Raman scattering effect weakens. The effect of stimulated Raman scattering on mode instability has also been studied. Due to that the stimulated Raman scattering effect is weak and that the fraction of Raman light is only a few percent, the stimulated-Raman-scattering-induced mode instability has not been observed in the experiment, and the observed mode instability is induced by ytterbium ion gain of signal laser. It also revealed that the stimulated Raman scattering has negligible influence on the mode instability induced by ytterbium ion gain.
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Yu CX, Shatrovoy O, Fan TY, Taunay TF. Diode-pumped narrow linewidth multi-kilowatt metalized Yb fiber amplifier. OPTICS LETTERS 2016; 41:5202-5205. [PMID: 27842093 DOI: 10.1364/ol.41.005202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate high brightness pumping of a multi-kilowatt Yb fiber amplifier in a bi-directional pumping configuration. Each pump outputs 2 kW in a 200 μm, 0.2 NA multimode fiber. Gold-coated specialty gain fibers, with a 17 μm mode field diameter and a 5 dB/m pump absorption, have been developed. The maximum fiber amplifier output power is 3.1 kW, limited by multimode instability, with 90% O-O efficiency and M2<1.15. The fiber amplifier linewidth is 12 GHz.
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Lee KH, Lee K, Kim Y, Cha YH, Lim G, Park H, Cho H, Jeong DY. Transverse mode instability induced by stimulated Brillouin scattering in a pulsed single-frequency large-core fiber amplifier. APPLIED OPTICS 2015; 54:189-194. [PMID: 25967616 DOI: 10.1364/ao.54.000189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/29/2014] [Indexed: 06/04/2023]
Abstract
We report the observation of transverse mode instability (TMI) in a pulsed single-frequency ytterbium-doped large-core fiber amplifier in which stimulated Brillouin scattering (SBS) is generated easily owing to the high peak power and narrow linewidth of the laser pulses. It was shown experimentally that the threshold of TMI is almost the same as that of SBS and that the suppression of SBS also increases the threshold of TMI, which indicates that the TMI originates from SBS in the fiber.
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Abstract
A model of transient modal instability in fiber amplifiers is presented. This model combines an optical beam propagation method that incorporates laser gain through local solution of the rate equations and refractive index perturbations caused by the thermo-optic effect with a time-dependent thermal solver with a quantum defect heating source term. This model predicts modal instability a fiber amplifier operating at 241, 270, and 287 Watts of output power characterized by power coupling to un-seeded modes, the presence of stable and unstable regions within the fiber, and rapid intensity variations along the fiber. The instability becomes more severe as the power is increased.
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Affiliation(s)
- Benjamin G Ward
- Laser and Optics Research Center, Department of Physics, United States Air Force Academy, 2354 Fairchild Drive Ste. 2A31, USAF Academy Colorado 80840, USA.
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Hansen KR, Alkeskjold TT, Broeng J, Lægsgaard J. Theoretical analysis of mode instability in high-power fiber amplifiers. OPTICS EXPRESS 2013; 21:1944-1971. [PMID: 23389177 DOI: 10.1364/oe.21.001944] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a simple theoretical model of transverse mode instability in high-power rare-earth doped fiber amplifiers. The model shows that efficient power transfer between the fundamental and higher-order modes of the fiber can be induced by a nonlinear interaction mediated through the thermo-optic effect, leading to transverse mode instability. The temporal and spectral characteristics of the instability dynamics are investigated, and it is shown that the instability can be seeded by both quantum noise and signal intensity noise, while pure phase noise of the signal does not induce instability. It is also shown that the presence of a small harmonic amplitude modulation of the signal can lead to generation of higher harmonics in the output intensity when operating near the instability threshold.
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Affiliation(s)
- Kristian Rymann Hansen
- Department of Photonics Engineering, Technical University of Denmark Bldg. 345v, DK-2800 Kgs. Lyngby, Denmark.
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