Author Affiliations
1Aerospace Laser Technology and System Department, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China2Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China3Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai 201800, Chinashow less
Fig. 1. High-power three-single-frequency laser achieved using sinusoidal modulation and optical fiber stress gradients
[51] Fig. 2. High-power narrow linewidth fiber lasers based on spectral modulation
[53] Fig. 3. The test results of the 4.23 kW fiber laser
[63]. (a) The curve of output laser power and backward light power versus pump power; (b) the spectral linewidth and signal-to-noise ratio of the output laser
Fig. 4. The spectrum after cascading PRBS and sinusoidal phase modulation, along with the forward output spectra at different power levels
[68] Fig. 5. The SBS enhancement factor varing with the spectral line spacing and the bandwidth of the filter
[57] Fig. 6. The situation of SBS threshold after PRBS modulation without filtering
[76] Fig. 7. The situation of SBS threshold after PRBS modulation and filtering
[76] Fig. 8. Using a semi-analytical model to calculate the SBS threshold after filtering PRBS modulation
[77] Fig. 9. Measurement of SBS threshold after filtered PRBS modulation
[77] Fig. 10. The time constant of the SBS establishment process
[78] Fig. 11. PRBS dwell time and SBS transient response
[78] Fig. 12. The functional form of the normalized effective Brillouin gain spectrum and spectral characterization of segmented parabolic phase-modulated optical fields
[79] Fig. 13. Comparison between simulation results (curves) and experimental data (dots) of SBS thresholds for segmented parabolic phase modulation at different
β values
[79] Fig. 14. Active mode control of high-power fiber lasers
[90] Fig. 15. The schematic diagram of the passive coherent combining principle in the optical feedback ring cavity
Fig. 16. 4-channel fiber laser self-imaging cavity coherent synthesis
[105] Fig. 17. Phase locking and phase coherence
[106] Fig. 18. Interference patterns under different phase states using a ring cavity coherent synthesis
[107] Fig. 19. High-power annular cavity coherent synthesis pattern and the output power of 1062 W
[107] Fig. 20. Schematic diagram of Dammann grating aperture filling principle
[113] Fig. 21. Fiber laser coherent synthesis device and synthesized spot pattern based on DOE
[113] Fig. 22. Spectral beam combining by diffraction grating
Fig. 23. Spectral synthesis of SBC using single MLD grating MOPA structure
Fig. 24. Schematic diagram of Aculight’s 30 kW fiber laser spectral synthesis
[129] Fig. 25. Aculight’s 30 kW fiber laser spectral synthesis spot and spectrogram
[129] Fig. 26. Schematic diagram of 4-way 8.2 kW spectral synthesis at Jena University in Germany
[132] Fig. 27. Dual grating spectral beam combining structure
Fig. 28. Experimental setup of 9.6 kW SBC
[136] Fig. 29. (a) Backscattering power versus output power; (b) emission spectrum and beam quality of 2.5 kW output beam; (c) 2 kW power level beam quality test
[48] Fig. 30. Spectral synthesis system with a total power of 11.27 kW
Fig. 31. Spectrum of the combined beam
Fig. 32. Combining power trend during the beam combining process
| Seed type | Advantage | Disadvantage |
|---|
| Narrow linewidth oscillator | Simple structure， strong anti-backscattering capability； high SBS threshold | Easily prone to SRS and spectral broadening， with low spectral energy concentration | | Narrowband ASE source | Relative oscillator， low forward power noise； high SBS threshold； wavelength and linewidth tunable | Complex structure； prone to SRS and spectral broadening， with low spectral energy concentration； relatively narrow linewidth oscillators have higher SRS and spectral broadening suppression capabilities | | Narrowband random laser | Relative oscillator， low forward power noise； high SBS threshold； the spectral broadening rate is slower than that of the oscillator | Complex structure； prone to SRS and spectral broadening， with low spectral energy concentration； relatively narrow linewidth oscillators exhibit higher SRS and spectral broadening suppression capabilities | | Spectral tuning single-frequency laser | Low forward power noise； low frequency noise， good coherence； high spectral energy concentration； tunable wavelength and linewidth； high SRS threshold， no spectral broadening | Complex structure； poor anti-return ability； low SBS threshold， strong dependence on spectral modulation signals |
|
Table 1. Advantages and disadvantages of high-power narrow linewidth fiber amplification using different types of seed sources
| Year | Institution | Modulation method | Polarization extinction ratio /dB | Power / kW | Linewidth | M2 | Reference |
|---|
| 2014 | Air Force Research Laboratory | PRBS | Non | 1.17 | 3 GHz@3 dB | 1.2 | ［47］ | | 2015 | Shanghai Institute of Optics and Fine Mechanics | WNS | Non | 2.52 | 50 GHz@3 dB | =1.191，=1.186 | ［48］ | | 2016 | National University of Defense Technology | Three-stage cascaded sinusoidal phase modulation | 15.5 | 1.89 | 45 GHz@3 dB | =1.19，=1.27 | ［49］ | | 2016 | National University of Defense Technology | WNS | 18.3 | 2.43 | 67.6 GHz@3 dB | | ［50］ | | 2017 | Shanghai Institute of Optics and Fine Mechanics | Sinusoidal phase modulation | 18 | 0.302 | Triple-frequency | 1.04 | ［51］ | | 2018 | China Academy of Engineering Physics | Two-stage cascaded WNS | Non | 3.5 | 46.3 GHz@3 dB | ~1.9 | ［52］ | | 2019 | Shanghai Institute of Optics and Fine Mechanics | WNS and sinusoidal phase modulation | Non | 3.01 | 48 GHz@3 dB | 1.17 | ［53］ | | 2019 | University of Science and Technology of China | Two-stage cascaded WNS | Non | 3.7 | 80.1 GHz@3 dB | =1.358， =1.202 | ［54］ | | 2019 | China Academy of Engineering Physics | WNS | 13 | 1.5 | 13 GHz@3 dB | 1.14 | ［55］ | | 2019 | National University of Defense Technology | WNS | PM | 0.827 | 1.8 GHz@3 dB | <1.5 | ［56］ | | 2020 | Shanghai Institute of Optics and Fine Mechanics | PRBS | Non | 1.27 | 2.2 GHz | =1.14，=1.20 | ［57］ | | 2020 | China Academy of Engineering Physics | Two-stage cascaded WNS | 14 | 2.62 | 32 GHz@3 dB | <1.3 | ［58］ | | 2020 | China Academy of Engineering Physics | WNS | Non | 3 | 0.18 nm@3 dB | <1.2 | ［59］ | | 2021 | National University of Defense Technology | WNS | Non | 4.92 | 0.59 nm@3 dB | M2=1.22 | ［60］ | | 2021 | China Academy of Engineering Physics | AWG | 15 | 3.25 | 20 GHz@3 dB | 1.22 | ［61］ | | 2021 | China Academy of Engineering Physics | Two-stage cascaded WNS | Non | 5.07 | 0.37 nm@3 dB | =1.252， =1.322 | ［62］ | | 2022 | Shanghai Institute of Optics and Fine Mechanics | Cascaded phase modulation | Non | 4.23 | 68 GHz@3 dB，43.5 GHz@RMS linewidth | 1.15 | ［63］ | | 2022 | National University of Defense Technology | WNS | 13.9 | 3.96 | 0.62 nm@3 dB | =1.31，M=1.41 | ［64］ | | 2022 | National University of Defense Technology | WNS | Non | 6.12 | 0.86 nm@3 dB | =1.43，M=1.36 | ［65］ | | 2022 | China Academy of Engineering Physics | | 17.7 | 4.45 | 0.08 nm@3 dB | =1.28，=1.25 | ［66］ | | 2022 | South China University of Technology | WNS | Non | 2.02 | 4.7 GHz@3 dB | 1.2 | ［67］ | | 2023 | Shanghai Institute of Optics and Fine Mechanics | cascaded PRBS and sinusoidal phase modulation | Non | 4.93 | 46 GHz @RMS linewidth | <1.2 | ［68］ | | 2023 | National University of Defense Technology | WNS | 11.8 | 5.023 | 0.38 nm@3 dB | | ［69］ | | 2023 | China Academy of Engineering Physics | AWG | 14.91 | 3 | <10 GHz @3 dB | =1.134，=1.178 | ［70］ | | 2023 | China Academy of Engineering Physics | | >18.3 | 4 | 9.8 GHz@RMS linewidth | 1.18 | ［71］ | | 2023 | China Academy of Engineering Physics | | 16.5 | 5.04 | 0.267 nm @3dB， 0.2 nm@RMS linewidth | =1.27，=1.29 | ［72］ | | 2023 | Agency for Defense Development， Republic of Korea | Quasi-flat-top PRBS modulation | 15 | 2.01 | 8 GHz@3 dB | =1.32，=1.26 | ［73］ | | 2023 | Shanghai Jiao Tong University | Binary multi-tone signal modulation | Non | 2.234 | 10 GHz@3 dB | | ［74］ | | 2023 | China Academy of Engineering Physics | | 20 | 5 | 9.93 GHz @RMS linewidth | =1.28，=1.25 | ［75］ |
|
Table 2. Research progress on high-power fiber amplification using spectrally controlled single-frequency seed sources
| Year | Institution | Method | Device | Probe | Power /W | Reference |
|---|
| 2017 | National University of Defense Technology | SPGD | Polarization controller | PD | LP01：486， LP11：521 | ［89］ | | 2020 | National University of Defense Technology | | Acoustic-induced fiber grating | | LP01：5.85， LP11：6.06 | ［94］ | | 2021 | Shanghai Institute of Optics and Fine Mechanics | SPGD | Polarization controller | PD | LP01：1389， LP11：1396 | ［90］ | | 2022 | National University of Defense Technology | | Acoustic-induced fiber optic grating | | LP01：105.7， LP11：101.3 | ［93］ |
|
Table 3. Research progress in active mode control technology
| Serial number | Wavelength /nm | Output power /kW | Total power /kW |
|---|
| 1 | 1058.5 | 1.58 | | | 2 | 1064.2 | 2.23 | | | 3 | 1068.0 | 1.64 | | | 4 | 1070.9 | 1.62 | | | 5 | 1075.9 | 1.66 | | | 6 | 1081.0 | 1.61 | | | 7 | 1082.5 | 1.81 | 12.15 |
|
Table 4. The output power of the fiber laser array
![High-power three-single-frequency laser achieved using sinusoidal modulation and optical fiber stress gradients[51]](/richHtml/zgjg/2024/51/11/1101021/img_01.jpg)
![High-power narrow linewidth fiber lasers based on spectral modulation[53]](/richHtml/zgjg/2024/51/11/1101021/img_02.jpg)
![The test results of the 4.23 kW fiber laser[63]. (a) The curve of output laser power and backward light power versus pump power; (b) the spectral linewidth and signal-to-noise ratio of the output laser](/Images/icon/loading.gif){kind=icon}
