|
1
|
Liu J, Zeng L, Wang X, Ye Y, Wang P, Wu H, Shi C, Xi X, Zhang H, Ning Y, Xi F. 2 × 4 kW near-single-mode laser output assisted by an optimized bidirectional oscillating-amplifying integrated fiber laser configuration. OPTICS EXPRESS 2024; 32:20035-20049. [PMID: 38859122 DOI: 10.1364/oe.523781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 05/02/2024] [Indexed: 06/12/2024]
Abstract
Bidirectional output oscillating-amplifying integrated fiber laser (B-OAIFL) can achieve the two-ports laser amplification based on a single cavity, showcasing a promising prospect. In order to improve both the laser power and beam quality, we first simulate and optimize the stimulated Raman scattering (SRS) effect in the B-OAIFL. The simulation results show the SRS effect can be suppressed by optimizing the diameter as well as the length of the active fiber at different locations. With the guidance of theoretical and experimental analysis for the combined suppression of SRS and transverse mode instability (TMI), a near-single-mode B-OAIFL with 2 × 4 kW was demonstrated. Based on this foundation, we further devoted ourselves to the pursuit of the optimization of the structure and performance. The necessity of the configuration of side pump, which was initially introduced for its exceptional performance in stabilizing temporal chaos, was reevaluated in detail. With its negative impacts on efficiency improvement and SRS suppression were analyzed and verified, we removed this configuration and finally demonstrated a more simplified design with superior performance. A total bidirectional output of 8105 W was achieved, with an O-O efficiency of 79.6% and a near-single-mode beam quality of M A 2∼1.36,M B 2∼1.63. No signs of TMI were observed, and the signal-to-SRS suppression ratio was over 38 dB. The results still demonstrate a promising potential for power scaling based on this configuration and parameters.
Collapse
|
|
2
|
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 PMCID: PMC11154347 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.
Collapse
Affiliation(s)
- Lingfa Zeng
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
| | - Xinyi Ding
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
| | - Jiaqi Liu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
| | - Xiaolin Wang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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; (L.Z.); (X.D.); (J.L.); (Y.Y.); (H.W.); (P.W.); (X.X.); (H.Z.); (C.S.); (F.X.); (X.X.)
- 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
| |
Collapse
|
|
3
|
Liu J, Zeng L, Wang P, Wu H, Xi X, Shi C, Zhang H, Wang X, Ning Y, Xi F. Demonstration of 3kW × 2 ports bidirectional output oscillating-amplifying integrated fiber laser employing chirped and tilted fiber Bragg gratings for co-SRS suppression. OPTICS EXPRESS 2023; 31:28400-28412. [PMID: 37710894 DOI: 10.1364/oe.494530] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 08/01/2023] [Indexed: 09/16/2023]
Abstract
Bidirectional output oscillating-amplifying integrated fiber laser (B-OAIFL) is a newly developed configuration with many advantages like compactness and good reliability. In this work, a B-OAIFL with a low time-stabilized threshold was constructed by employing a pair of side pump/signal combiner in the oscillating section, which demonstrates smooth temporal characteristics with no pulse detected by the photodetector at the output power level of only a few of tens Watts. We investigated the effect of side pumping on the Raman Stokes light and verified its contribution to mitigating the temporal-chaos-induced stimulated Raman scattering (SRS). The phenomenon of co-SRS caused by the mutual excitation of backward Stokes light from two amplifying sections under bidirectional pumping was first reported and studied. A pair of chirped and tilted fiber Bragg gratings (CTFBGs) were applied between the oscillating and amplifying sections to suppress the co-SRS, and the effect of the number of CTFBGs on the suppression of co-SRS was studied in detail experimentally. Finally, we successfully suppressed the co-SRS, and achieved a 3kW × 2 ports laser output, with a near-single-mode beam quality of M A 2∼1.3,M B 2∼1.4. In contrast, without the use of CTFBG, only a 2 kW-level output was obtained from each port, limited by co-SRS (with an SRS suppression ratio of less than 15 dB). The maximum output power of end A and end B is 3133 W and 3213 W, with the SRS suppression ratio of about 27.6 dB and 28.1 dB, respectively. No TMI features were observed under bidirectional pumping. The results demonstrate a significant potential for further power scaling based on this configuration. To the best of our knowledge, it is the highest output power achieved based on the B-OAIFL.
Collapse
|
|
4
|
Lin W, Bussières-Hersir MH, Auger M, Vincelette A, Rochette M. 3 kW forward-pumped fiber laser via pump recycler. APPLIED OPTICS 2023; 62:4490-4495. [PMID: 37707141 DOI: 10.1364/ao.489762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/16/2023] [Indexed: 09/15/2023]
Abstract
We report a single-end forward-pumped fiber laser with a record high output power of 3 kW. The laser is assembled exclusively from commercially widespread components such as the Yb-doped fiber with core/cladding diameter of 20/400 µm, pump laser diodes at an emission wavelength of 915 nm, and a signal and pump fiber combiner that serves as the pump recycler. The record high power arises from the combination of the 915 nm pumping and pump recycler with an effective reflectivity of 78%, increasing simultaneously the thresholds for stimulated Raman scattering and transverse mode instability (TMI). The length of the oscillator was also varied experimentally from 20 m to 5 m, showing a contrast of up to 19% in the TMI threshold. This shows the importance of accurately partitioning the Yb-doped fiber length in between the oscillator and amplifier sections to minimize the impact of TMI.
Collapse
|
|
5
|
Yan D, Liao R, Guo C, Zhao P, Shu Q, Lin H, Wang J, Tao R. A 3.7-kW Oscillating-Amplifying Integrated Fiber Laser Featuring a Compact Oval-Shaped Cylinder Package. MICROMACHINES 2023; 14:264. [PMID: 36837964 PMCID: PMC9961345 DOI: 10.3390/mi14020264] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 06/01/2023]
Abstract
Combining the advantages of high efficiency, environmental robustness, and anti-reflection behavior, oscillating-amplifying integrated fiber lasers have become popular for use in high-power laser structures in industrial applications, wherein the size of the laser source matters. Here, an oscillating-amplifying integrated fiber laser in an oval-shaped cylinder package has been proposed and demonstrated, the footprint for which only occupies an area of 0.024 m2 apart from the pump diode, which is much smaller than in traditional planar fiber laser packages. Numerical simulations have been carried out, which have revealed that an oval-shaped cylinder package can effectively suppress the high-order mode in large mode area fiber setups and thereby benefit the integration of fusion points and the unpackaged elements at the same time. Over 3.7 kW of transverse mode instability (TMI)-free output power has been obtained, with a slope efficiency higher than 80%. With a custom-made chirped and tilted fiber Bragg grating (CTFBG), the Raman suppression ratio is improved to reach 38 dB at peak output power. The oval-shaped design has been verified to assist with the realization of TMI suppression and improve the integration of high-power fiber lasers. To the best of our knowledge, this fiber laser has among the smallest footprints of the various fiber sources at such high-power operating levels.
Collapse
Affiliation(s)
| | - Ruoyu Liao
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | | | | | | | | | | | - Rumao Tao
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| |
Collapse
|
|
6
|
Lin W, Desjardins-Carrière M, Iezzi VL, Vincelette A, Bussières-Hersir MH, Rochette M. Effective all-fiber pump recycler for kilowatt fiber lasers. APPLIED OPTICS 2022; 61:6092-6096. [PMID: 36255851 DOI: 10.1364/ao.464425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/23/2022] [Indexed: 06/16/2023]
Abstract
We report an effective pump recycler for industrial kilowatt fiber lasers. The pump recycler is a (6+1)×1 tapered fiber bundle, with signal ports of Ge-doped fiber (GDF) with core/cladding diameters of 20/400 µm and pump fiber ports (PFPs) with core/cladding diameters of 135/155 µm. By splicing PFPs in pairs, 77.9% of the residual pump light reaching the pump recycler is sent back to the cladding of the GDF. The insertion of a pump recycler increases the power conversion efficiency (PCE) of a fiber laser using an Yb-doped fiber (YDF) from 61.0% to 70.5%, with a maximum output power of 2.78 kW. The laser with a 20 m long YDF and pump recycler compares well to another laser using a 40 m long YDF without pump recycler. In both cases, the PCE is comparable but the laser with a 20 m long YDF and pump recycler benefits from reduced stimulated Raman scattering (SRS), thus enabling an 80% increase in Raman threshold. By giving access to short YDF length, the tapered fiber bundle represents an effective pump recycler since it enables reducing SRS while keeping a large PCE.
Collapse
|
|
7
|
Zeng L, Xi X, Zhang H, Yang B, Wang P, Wang X, Xu X. Demonstration of the reliability of a 5-kW-level oscillating-amplifying integrated fiber laser. OPTICS LETTERS 2021; 46:5778-5781. [PMID: 34780460 DOI: 10.1364/ol.445153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 10/31/2021] [Indexed: 06/13/2023]
Abstract
A novel fiber laser called an oscillating-amplifying integrated fiber laser was studied experimentally, in which the oscillating section and amplifying section share the pump between them. Based on this configuration, a 5-kW fiber laser system with optical-optical efficiency of 80.9% and M2 factor of 1.5 was achieved. The startup and shutdown sequence of the laser was studied in detail. When pumps of the laser were deliberately turned on in an inverted order, such as switching on/off the amplifying section before/after the oscillating section, which is normally disastrous in a classic fiber amplifier, the laser system turned out to operate stably at full power level. Thus, it is verified that there is no priority between the amplifier and the seed in this laser system. It combines the advantages of conventional fiber oscillators and fiber amplifiers, including high efficiency, high reliability, good anti-backreflection, and simple control logic.
Collapse
|
|
8
|
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.
Collapse
|
|
9
|
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.
Collapse
|