• Title/Summary/Keyword: Laser diodes

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Implementation of a Projection System for Projecting an Image with Laser Diodes (레이저 다이오드를 이용한 영상 투사용 프로젝션 시스템 구현)

  • Kim, Ki-Jun;Lee, Young-Chul
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.1157-1160
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    • 2005
  • 본 논문에서는 레이저 다이오드(Laser Diode, LD)를 배열시키고 회전 다면경(Polygon Mirror)의 반사각 및 회전다면경의 기하학적 프로젝션 시스템 설계를 통하여 2D-레이저 프로젝션 시스템을 구현하였다. 제안한 회전다면경과 레이저 다이오드 배열을 적용하석 영상 동기 시켜 레이저 배열을 적용한 레이저 디스플레이 시스템을 최종적으로 설계하고 실제 제작을 통해서 시스템을 검증하였다.

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Performance of Hybrid Laser Diodes Consisting of Silicon Slab and InP/InGaAsP Deep-Ridge Waveguides

  • Leem, Young-Ahn;Kim, Ki-Soo;Song, Jung-Ho;Kwon, O-Kyun;Kim, Gyung-Ock
    • ETRI Journal
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    • v.32 no.2
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    • pp.339-341
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    • 2010
  • The fundamental transverse mode lasing of a hybrid laser diode is a prerequisite for efficient coupling to a single-mode silicon waveguide, which is necessary for a wavelength-division multiplexing silicon interconnection. We investigate the lasing mode profile for a hybrid laser diode consisting of silicon slab and InP/InGaAsP deep ridge waveguides. When the thickness of the top silicon is 220 nm, the fundamental transverse mode is lasing in spite of the wide waveguide width of $3.7{\mu}m$. The threshold current is 40 mA, and the maximum output power is 5 mW under CW current operation. In the case of a thick top silicon layer (1 ${\mu}m$), the higher modes are lasing. There is no significant difference in the thermal resistance of the two devices.

TEM Observations on the Blue-green Laser Diode (청녹색 레이저 다이오드 구조에 관한 TEM 관찰)

  • Lee, Hwack-Joo;Ryu, Hyun;Park, Hae-Sung;Kim, Tae-Il
    • Applied Microscopy
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    • v.27 no.3
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    • pp.257-263
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    • 1997
  • Microstructural characterizations of II-VI blue laser diodes which consist of quaternary $Zn_{1-x}Mg_xS_ySe_{l-y}$ cladding layer, ternary $ZnS_ySe_{l-y}$ guiding layer and $Zn_{0.8}Cd_{0.2}Se$ quantum well as active layer were carried out using the transmission electron microscope working at 300 kV. Even though the entire structure is pseudomorphic to GaAs substrate, the structure had contained numerous extended stacking faults and dislocations which had created at ZnSe/GaAs interfaces and then further grown to the top of the epilayers. These faults might be expected to cause the degradation and shortening the lifetime of laser devices.

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Recent Progress on Voltage Drop Compensation in Top Emission Organic Light Emitting Diodes (OLED)

  • Jeong, Byoung-Seong
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.1
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    • pp.49-54
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    • 2020
  • The voltage drop due to the thin cathode film at the large size top emission OLED panel was successfully compensated with making electrical contact between thin cathode and anode auxiliary electrode by 355nm wavelength of laser. It was found that the luminance uniformity dramatically increased from around 15% to more than 80% through this electrical compensation between thin cathode and anode auxiliary electrode. Moreover, the removing process for EL materials on the anode auxiliary electrode process by laser was very reliable and stable. Therefore, it is thought that the EL removal method using laser to make electrical contacts is very appropriate to mass production for such a large size top emission OLEDs to obtain high uniformity of luminance.

Chaos Characteristics of Laser Diodes with External Optical Feedback (외부 광귀환이 있는 레이저 다이오드의 혼돈특성)

  • 양동석;한영진;김창민
    • Korean Journal of Optics and Photonics
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    • v.5 no.3
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    • pp.394-403
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    • 1994
  • Chaos characteristics of laser diodes with external optical feedback is investigated. For a FabryPerot resonator laser, optical feedback by external mirror is assumed. The simulation is performed in such a way that a current of $1.3J_{th}$ is injected into the $1.3{\mu}m$wavelength "InGaAsP" buried hetero structure laser. With the increment of K, the system shows the evolution of four steps as follows: i) When the optical feedback coefficient K is very small, the relaxation oscillation is damped and the system reaches the steady state showing the stable operation characteristics. ii) As K increases a little bit, the relaxation oscillation is not damped any more and the system begins to maintain the periodic oscillation. iii) When K is increased further, the oscillation shows the larger amplitude and the long periodic length. iv) When K is increased very large, the system gets unstable and enters into the coherejlce collapse state. state.

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

  • Oh Su Hwan;Lee Chul-Wook;Kim Ki Soo;Ko Hyunsung;Park Sahnggi;Park Moon-Ho;Lee Ji-Myon
    • Korean Journal of Optics and Photonics
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    • v.15 no.5
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    • pp.469-474
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    • 2004
  • We have fabricated and designed wavelength-tunable sampled grating distributed Bragg reflector laser diodes(SGDBR-LD) by using, for the first time, planar buried heterostructures(PBH). The diodes have low threshold current values and high-performance of laser operation. Growth condition using metal organic chemical vapor deposition(MOCVD) was optimized for the formation of a good butt-coupling at the interface. A maximum output power of the fabricated device was 20 mW under 200 mA continuous wave(CW) operation at $25^{\circ}C$. Average threshold current and voltage were 12 mA and 0.8 V, approximately. This output power is higher than those of ridge waveguide(RWG) and buried ridge stripe(BRS) structures by amounts of 9 mW and 13 mW, respectively. We obtained a tuning range of 44.4nm which is well matched with the target value of our design. The side mode suppression ratio of more than 35 dB was obtained for the whole tuning range. Optical output power variation was less than 5 dB, which is 4 dB smaller than that of RWG structures.

Effect of Stripe Width on Threshold in Single Quantum Well Laser Diodes (단일양자우물 Laser Diode에서 Stripe 폭이 문턱치에 미치는 영향)

  • 이성재
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.3
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    • pp.591-596
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    • 1994
  • Threshold dependence on stripe width in gain-guided single quantum well lasers has been examined by complex domain effective index method. It is found, in narrow stripe regime, that the lateral optical confinement estimated by newly introduced parameters decreases very rapidly as the transverse optical confinement factor decreases. Thus, in a single quantum well laser with a usually very small, the optical confinement may become very poor depending on stripe width not only in the transverse but also in the lateral direction, further enhancing the gain saturation and often leading to an anomalously high threshold current. The understanding of rather anomalous threshold dependence on stripe width will be very important in optimization of quantum well laser diode structure.

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