• 제목/요약/키워드: High Power Diode Laser

검색결과 142건 처리시간 0.022초

Cascaded Volume Bragg Grating for Narrow Spectral Linewidth in High-power Laser Diodes

  • Lee, Dong-Jin;Shim, Gyu-Beom;Jeong, Ji-Hun;O, Beom-Hoan
    • Current Optics and Photonics
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    • 제6권3호
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    • pp.282-287
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    • 2022
  • Narrowing the spectral linewidth and improving the wavelength stability of high-power laser diodes (HPLDs) are both in high demand for rapidly maturing industrial laser applications. In this study, we investigate the spectral behavior of a commercial HPLD bar module composed of 19 laser diodes (LDs) in a single-layered bar with a built-in volume Bragg grating (VBG) and an additional cascaded VBG. Optical loss due to the extra cascaded VBG is kept below 5% when the optical output is 5 W or more. The full width at half maximum of the Fabry-Perot peak from the cascaded VBG is reduced to about 12.4% and 29.1% at the edge (1st LD) and center (10th LD) of the HPLD bar module respectively, compared to using only a built-in VBG at an optical power of 10 W or more. In addition, fine wavelength tuning is achieved by temperature control of the extra VBG, and the obtained wavelength-tuning range amounts to about 10.6 pm/K.

고출력 광섬유 레이저 냉각판 설계과정에서 나타난 열전달 이론, CFD 및 실험 결과값의 비교 (Comparison of Heat Transfer Theory, CFD and Experimental Results in the Design Process of High-Power Fiber Laser Cooling Plate)

  • 김태우;이강인;정민완;정예지;고광웅;이용수
    • 한국군사과학기술학회지
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    • 제24권6호
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    • pp.629-637
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    • 2021
  • For the stabilization of laser output power and wavelength of the high power fiber laser, the cooling plate must be properly taken into account. In this study, three analyzing methods which are heat transfer theory, CFD and experiment are used to analyze cooling plate performance by measuring pump Laser Diode(LD) temperature. Under limited operating conditions of a cooling plate, the internal flow of cooling plate is transitional flow so that the internal flow is assumed to be laminar and turbulence flow and conducted theoretical calculation. Through CFD, temperature of pump LD and characteristics of the internal flow were analyzed. By the experiment, temperature of pump LD was measured in real conditions and the performance of the cooling plate was verified. The results of this study indicate that three analyzing methods are practically useful to design the cooling plate for the high power fiber laser or similar things.

Lateral Far-field Characteristics of Narrow-width 850 nm High Power GaAs/AlGaAs Laser Diodes

  • Yang, Jung-Tack;Kwak, Jung-Geun;Choi, An-Sik;Kim, Tae-Kyung;Choi, Woo-Young
    • Current Optics and Photonics
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    • 제6권2호
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    • pp.191-195
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    • 2022
  • We investigate the lateral far-field pattern characteristics, including divergence angle change and far-field pattern analysis as output power increases, of narrow-emitter-width 850 nm GaAs/AlGaAs laser diodes (LDs). Each LD has a cavity of 1200 and 1500 ㎛ and narrow emitter width of 2.4 ㎛ for the top and 4.6 ㎛ for the bottom. The threshold currents are 35 and 40 mA, and L-I kinks appear at power levels of 326 and 403 mW, respectively. The divergence angle tends to increase due to the occurrence of first-order lateral mode and the thermal lensing effect. But with the L-I kink, the divergence angle decreases and the far-field pattern becomes asymmetric. This is due to coherent superposition between the fundamental and the first-order lateral mode. We provide detailed explanations for these observations based on high-power laser diode simulation results.

실시간 출력 제어를 통한 구상흑연 주철의 레이저 표면경화 특성 (Characteristics of Surface Hardening by Laser Power Control in Real Time of Spheroidal Graphite Cast Iron)

  • 김종도;송무근
    • 한국레이저가공학회지
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    • 제18권2호
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    • pp.1-4
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    • 2015
  • This study is related to the surface hardening treatment to spheroidal graphite cast iron for die by using high power diode laser. Laser device used in this experiment is capable of real-time laser power control. This is because the infrared temperature sensor (two color pyrometer) attached to the optical system measures the surface temperature of specimen and adjusts the laser power in real time. The surface treatment was carried out with the change of heat treatment temperature at the beam travel speed 3 mm/sec. Hardened width and depth was measured and hardened zone was analyzed by micro vickers hardness test in order to research the optimum condition of heat treatment. The changes in microstructure of the hardened zone also was examined. As a result of hardness measurement and observations on microstructure of hardened zone, hardness increased over three times as compared with base metal because the martensite was formed on the matrix structure.

저 전류 및 고 효율로 동작하는 양자 우물 매립형 butt-coupled sampled grating distributed bragg reflector laser diode 설계 및 제작 (Design and Fabrication of butt-coupled(BT) sampled grating(SG) distributed bragg reflector(DBR) laser diode(LD) using planar buried heterosture(PBH))

  • 오수환;이철욱;김기수;고현성;박상기;박문호;이지면
    • 한국광학회지
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    • 제15권5호
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    • pp.469-474
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    • 2004
  • 본 논문에서는 저 전류 및 고 효율로 동작하는 planar buried heterostructure(PBH) 구조로 sampled grating(SG) distributed bragg reflector(DBR) laser diode(LD)를 처음으로 설계하고 제작하였다. 특히 활성층과 도파로층의 높은 결합 효율을 얻기 위해 건식 식각과 습식 식각을 같이 사용하여 결함이 거의 없는 butt-coupling(BT) 계면을 형성하였다. 제작된 파장 가변레이저의 평균 발진 임계전류는 약 12 mA로 ridged waveguide(RWG)와 buried ridge stripe(BRS) 구조로 제작된 결과 보다 두 배 정도 낮게 나타났으며, 광 출력은 200 mA에서 약 20 mW 정도로 RWG 와 BRS 보다 각각 9 mW, 13 mW 더 우수하게 나타났다. 그리고 파장 가변 영역을 측정한 결과 44 nm로 설계결과와 일치하였으며, 최대 파장 가변 영역 안에서 출력 변화 폭이 5 dB 이내로서 RWG 구조의 9 dB보다 출력변화 폭이 4 dB 적게 나타났다. 전체 파장 가변 영역에서 SMSR이 35 dB 이상으로 나타났다.

Laser Scanning Unit을 위한 8빔 레이저 다이오드 개발 (8 Beam Laser Diode Development for Laser Scanning Unit)

  • 송대권;박종근;김재규;박정현;소상영;곽윤석;양민식;최안식;김태경
    • 한국광학회지
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    • 제21권3호
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    • pp.111-117
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    • 2010
  • 레이저 프린터 및 OA복합기기 내부의 감광 드럼에 빛을 조사하는 핵심 광 모듈인 Laser Scanning Unit(LSU)의 광원으로 사용할 수 있는 발진파장 780 nm, 광 출력 10 mW의 모노리식 집적형 8빔 레이저 다이오드를 개발하였다. 개발된 8-빔 소자의 레이저 빔들의 각각의 물리적 간격은 $30\;{\mu}m$ 이며, 각 빔을 독립적으로 작동시키기 위해서, 공중배선공정을 신규로 개발하였다. 개발된 8빔 레이저 다이오드의 전기 및 광학적 특성 측정 결과 레이저 프린터 및 복합기의 LSU에 사용 가능함을 검증하였다.

Characteristics of Si3N4 Laser Assisted Machining according to the Laser Power and Feed Rate

  • Kim, Jong-Do;Lee, Su-Jin;Suh, Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권7호
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    • pp.963-970
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    • 2010
  • This study makes an estimate of the laser-assisted machining (LAM) of an economically viable process for manufacturing precision silicon nitride ceramic parts using a high-power diode laser (HPDL). The surface is locally heated by an intense laser source prior to material removal, and the resulting softening and damage of the workpiece surface simplify the machining of the ceramics. The most important advantage of LAM is its ability to produce much better workpiece surface quality compared to conventional machining. Also important are its larger material removal rates and longer tool life. The cutting force and surface temperature were measured on-line using a pyrometer and a dynamometer, respectively. Tool wear, chips and the surface of the workpiece were measured using optical microscopy, and the surface and fractured cross-section of $Si_3N_4$ were measured by SEM. During the LAM process, the cutting force and tool wear were reduced and oxidation of the machined surface was increased according to the increase in the laser power. Moreover, the more the feed rate increased, the more the cutting force and tool wear increased.