• Title/Summary/Keyword: 마이크로칩 레이저

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Thermal Stress Relief through Introduction of a Microtrench Structure for a High-power-laser-diode Bar (높은 광출력을 갖는 Laser Diode Bar의 열응력 개선: 마이크로-홈 도입을 통한 응력 분포 변화 분석)

  • Jeong, Ji-Hun;Lee, Dong-Jin;O, Beom-Hoan
    • Korean Journal of Optics and Photonics
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    • v.32 no.5
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    • pp.230-234
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    • 2021
  • Relief of thermal stress has received great attention, to improve the beam quality and stability of high-power laser diodes. In this paper, we investigate a microtrench structure engraved around a laser-diode chip-on-submount (CoS) to relieve the thermal stress on a laser-diode bar (LD-bar), using the SolidWorks® software. First, we systematically analyze the thermal stress on the LD-bar CoS with a metal heat-sink holder, and then derive an optimal design for thermal stress relief according to the change in microtrench depth. The thermal stress of the front part of the LD-bar CoS, which is the main cause of the "smile effect", is reduced to about 1/5 of that without the microtrench structure, while maintaining the thermal resistance.

Experimental Analysis of Optical Fault Injection Attack for CRT-RSA Cryptosystem (CRT-RSA 암호시스템에 대한 광학적 오류 주입 공격의 실험적 연구)

  • Park, Jea-Hoon;Moon, Sang-Jae;Ha, Jae-Cheol
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.19 no.3
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    • pp.51-59
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    • 2009
  • The CRT-RSA cryptosystem is very vulnerable to fault insertion attacks in which an attacker can extract the secret prime factors p, q of modulus N by inserting an error during the computational operation on the cryptographic chip. In this paper, after implementing the CRT-RSA cryptosystem, we try to extract the secret key embedded in commercial microcontroller using optical injection tools such as laser beam or camera flash. As a result, we make sure that the commercial microcontroller is very vulnerable to fault insertion attacks using laser beam and camera flash, and can apply the prime factorization attack on CRT-RSA Cryptosystem.

Output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser (반도체레이저 단면여기 Nd:S-VAP 레이저의 내부공진기 제2고조파 출력 특성)

  • 박준학
    • Korean Journal of Optics and Photonics
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    • v.11 no.4
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    • pp.294-298
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    • 2000
  • The output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser were investigated. Nd:S-VAP is suitable for a microchip laser medium, which has a low threshold property because of a very high value of the stimulated emission cross-section and lifetime product. The threshold energy measured was 81 J.ll. The second harmonic output energy measured was $126\mu\textrm{J}$at a pump energy of $2\mu\textrm{J}$. We described for intracavity frequency doubling by using theoretical calculations. Q-switched second harmonic energy measured was $15\mu\textrm{J}$per pulse with a pulse-width of 26 ns. at a pump energy of 2 mJ and an $M^2$ of 1.47 represented a good beam quality. ality.

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Passive Alignment of Photodiode by using Visible Laser and Flip Chip Bonding (가시광 레이저를 이용한 수광소자의 수동정렬 및 플립칩본딩)

  • Yu, Chong-Hee;Lee, Sei-Hyoung;Lee, Jong-Jin;Lim, Kwon-Seob;Kang, Hyun-Seo
    • Journal of the Microelectronics and Packaging Society
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    • v.14 no.3
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    • pp.7-13
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    • 2007
  • In the optical module for optical communications, the flip chip bonding is used fer the precise alignment of the optical fiber and optical device. In flip chip bonding, the optical device is aligned and welded while observing the alignment mark of substrate and chip by using flip chip bonder in order to bond the optical device at the exact position. In this research, optical passive alignment method of photodiode(PD) flip chip bonding is suggested for low cost optical subassembly. By using the visible He-Ne laser (633nm wavelength), photodiode is easily aligned with emitting spot on the optical fiber with the help of stereoscopic alignment system. We compensated wavelength dependent deviation about 4m to find out real alignment position of 1550nm input laser by ray tracing. The maximum optical coupling efficiency between the optical fiber and photodiode was about 23.3%.

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Optical characteristics of Nd:LSB microchip laser device (Nd:LSB 마이크로칩 레이저 광소자의 광학 특성)

  • Jang, Won-Kweon;Park, Jong-Seon;Kim, Tong-Yol;Yu, Young-Moon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.965-967
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    • 2003
  • Czochralski pulling method에 의해 성장된 고농도 도핑 Nd:LSB의 광학적 특성을 조사하였다. 결정 성장조건에 의해 달라지는 space group은 지금까지 C2/c, R32, Cc와 C2등 4가지가 보고되었으며, 기본적으로 6방정계의 구조를 가지고 비선형 광학 결정으로서의 특성을 보였다. x선 회절 분석계를 이용하여 구조를 분석하였고, 도핑 농도에 따른 형광 수명의 변화, 분산곡선 특성을 조사하였다. 또한 흡수 및 저온 형광 스펙트럼을 이용하여 도핑 농도 및 space group의 변화에 따른 에너지 준위의 변화를 관찰하고 비교하였다.

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Analysis of Transmission Infrared Laser Bonding for Micro Polymer Devices (폴리머 마이크로 칩에 대한 레이저 투과 마이크로 접합)

  • Kim, Ju-Han;Sin, Gi-Hun
    • Proceedings of the KWS Conference
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    • 2005.06a
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    • pp.43-45
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    • 2005
  • A precise bonding technique, transmission laser bonding using energy transfer, for polymer micro devices is presented. The irradiated IR laser beam passes through the transparent part and absorbed on the opaque part. The absorbed energy is converted to heat and bonding takes place. In order to optimize the bonding quality, the temperature profile on the interface must be obtained. Using optical measurements of the both plates, the absorbed energy can be calculated and heat transfer model was applied for obtaining the transient temperature profile. The transmission laser bonding has a potential in the local precise bonding in MEMS or Lab-on-a-chip.

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Single Longitudinal Mode Operation in Nd:YVO$_4$ Microchip Laser (Nd:YVO$_4$ 마이크로칩 레이저의 단일 종모드 동작)

  • Ji, Myeong-Hun;Kim, Gyo-Jun;Lee, Yeong-U
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.51 no.6
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    • pp.260-264
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    • 2002
  • We developed LD Pumped Nd:$VVO_4$ microchip laser with the cavity length of 1mm. The microchip laser output was 87.5㎽ at the wavelength of 1063.9nm with the input power of 241㎽ at the wavelength of 809nm. The slope efficiency was 40.7% and the threshold input power was 31.1㎽. We have also defined input power limit for the single longitudinal mode operation theoretically. It was 2.5 times larger than that of threshold input intensity. According to the results of simulation, the Nd:YVO$_4$ microchip laser can be operated with the maximum output of 15㎽ for the single longitudinal mode up to the input power of 77.75㎽.

Operational and Thermal Characteristics of a Microchip Yb:YAG Laser (마이크로 칩 Yb:YAG 레이저의 동작 및 열적 특성)

  • Moon, Hee-Jong;Hong, Sung-Ki;Lim, Chang-Hwan
    • Korean Journal of Optics and Photonics
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    • v.22 no.2
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    • pp.96-101
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    • 2011
  • Operational and thermal characteristics of a thin disk Yb:YAG crystal with a thickness of 0.8 mm were studied using as a pumping source a fiber-coupled 930 nm laser diode. The heat generated in the crystal was dissipated by placing both surfaces in contact with copper plates with central hole, and the dependence of the temperature change in the illuminated spot on hole size was investigated by measuring the spectral change of the lasing peaks. The slope efficiency and optical-to-optical efficiency with respect to the LD pump power were as high as 42.2% and 34.8%, respectively. The temperature at the illuminated spot increased with diode current and with increasing hole size of the copper plate. When the hole size considerably exceeded the crystal thickness, the temperature rise deviated from the linear increase at high pump power.

Design and Development of Asymmetry Glass Array Lens (비축대칭 Glass Array Lens의 설계 및 개발)

  • Park, Soon-Sub;Hwang, Yeon;Lee, Ki-Young;Kim, Geon-Hee;Won, Jong-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.12
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    • pp.39-46
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    • 2008
  • Asymmetric glass lens core for portable projection optic system was designed and simulated. And it was machined by newly developed non-rotational ultra precision grinding method. With the designed lens data which optimized for multi-collimation, we generated the we core surface data. Mold pressing conditions analyzed by FEM. In the machining process, ground profile errors were compensated based on measured data, minimized feed rate and depth of cut. The deviations of machined core profile were acceptable level for glass mold press. Mold pressed glass array lens was coated with $SiO_2\;and\;Ta_2O_5$ for anti-reflection.