• Title/Summary/Keyword: 유도 브릴루앙 산란

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A Study of the Output Characteristics of a 1-kW-class Narrow-bandwidth PM Fiber Laser Depending on Its Pumping Structure (펌핑 구조에 따른 1 kW급 협대역 편광 유지 광섬유 레이저의 출력 특성 연구)

  • Kim, Tae Hyoung;Jeong, Seong Mook;Kim, Ki Hyuck;Lee, Sung Hun;Yang, Hwan Seok
    • Korean Journal of Optics and Photonics
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    • v.32 no.4
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    • pp.187-194
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    • 2021
  • This paper presents a study of laser output characteristics. We fabricated a MOPA (master oscillator power amplifier)-type high-power, narrowbandwidth fiber laser with a bidirectional pumping configuration in its main amplifier. As signal beams, light sources with bandwidths of 3 GHz and 10 GHz-phase-modulated through a PRBS (pseudo-random binary sequence)-were used interchangeably. Furthermore, the characteristics of the SBS (stimulated Brillouin scattering) were analyzed using a signal beam with 3 GHz bandwidth, by adjusting the forward to backward pumppower ratio. Moreover, the characteristics of the transverse mode instability were analyzed by adjusting the forward to backward pump-power ratio, using a signal beam with 10-GHz bandwidth. Finally, the output power from 10 GHz bandwidth was amplified to more than 1 kW using a forward to backward pump-power ratio of 1.6. The beam quality M2 was measured to be approximately 1.36, and the optical-to-optical efficiency was 80% at maximum output power.

High-beam-quality 2-kW-class Spectrally Combined Laser Using Narrow-linewidth Ytterbium-doped Polarization-maintaining Fiber Amplifiers (협대역 이터븀 첨가 편광유지 광섬유 증폭기를 이용한 고품질 2 kW급 파장제어 빔 결합 레이저)

  • Jeong, Hwanseong;Lee, Kwang Hyun;Lee, Junsu;Kim, Dong-Joon;Lee, Jung Hwan;Jo, Minsik
    • Korean Journal of Optics and Photonics
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    • v.31 no.5
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    • pp.218-222
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    • 2020
  • In this paper, we have experimentally demonstrated a 2-kW-class spectrally-beam-combined laser with high beam quality, using narrow-linewidth ytterbium-doped polarization-maintaining fiber amplifiers. Five fiber amplifiers with different center wavelengths were implemented for the spectrally-beam-combined laser. The center wavelengths of the five amplifiers were 1062, 1063, 1064, 1065, and 1066 nm, respectively. A phase-modulated laser diode was used as a seed source for each amplifier. The seed sources were modulated by filtered pseudorandom-bit-sequence (PRBS) signals 5 GHz in linewidth. The polarization-maintaining large-mode-area fiber with a core size of 30 ㎛ was used as a delivery fiber to mitigate the stimulated Brillouin scattering (SBS) effect. The laser beams from five amplifiers were spectrally combined by a multilayer dielectric diffraction grating. The maximum output power and beam quality M2 of the combined laser were measured to be 2.3 kW and 1.74, respectively.

Current Status and Prospects of High-Power Fiber Laser Technology (Invited Paper) (고출력 광섬유 레이저 기술의 현황 및 전망)

  • Kwon, Youngchul;Park, Kyoungyoon;Lee, Dongyeul;Chang, Hanbyul;Lee, Seungjong;Vazquez-Zuniga, Luis Alonso;Lee, Yong Soo;Kim, Dong Hwan;Kim, Hyun Tae;Jeong, Yoonchan
    • Korean Journal of Optics and Photonics
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    • v.27 no.1
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    • pp.1-17
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    • 2016
  • Over the past two decades, fiber-based lasers have made remarkable progress, now having reached power levels exceeding kilowatts and drawing a huge amount of attention from academy and industry as a replacement technology for bulk lasers. In this paper we review the significant factors that have led to the progress of fiber lasers, such as gain-fiber regimes based on ytterbium-doped silica, optical pumping schemes through the combination of laser diodes and double-clad fiber geometries, and tandem schemes for minimizing quantum defects. Furthermore, we discuss various power-limitation issues that are expected to incur with respect to the ultimate power scaling of fiber lasers, such as efficiency degradation, thermal hazard, and system-instability growth in fiber lasers, and various relevant methods to alleviate the aforementioned issues. This discussion includes fiber nonlinear effects, fiber damage, and modal-instability issues, which become more significant as the power level is scaled up. In addition, we also review beam-combining techniques, which are currently receiving a lot of attention as an alternative solution to the power-scaling limitation of high-power fiber lasers. In particular, we focus more on the discussion of the schematics of a spectral beam-combining system and their individual requirements. Finally, we discuss prospects for the future development of fiber laser technologies, for them to leap forward from where they are now, and to continue to advance in terms of their power scalability.