• 제목/요약/키워드: Laser threshold

검색결과 309건 처리시간 0.03초

Polarization Mode Coupling Constants in Solid-State Lasers

  • 박종대;조창호
    • 자연과학논문집
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    • 제17권1호
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    • pp.31-37
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    • 2006
  • We have found that the polarization mode coupling between the orthogonally linearly polarized dual mode laser results from the anisotropy of dipole moments. Rate equation analysis demonstrated that high anisotropy in dipole moment components can give rise to law intrinsic mode coupling constants while isotropic dipole moment components give high intrinsic mode coupling constant. The populations at active ion sites are shown to self-organize the populations such that laser mode gain is constant adove threshold while the gain contributions from the each site adjust themselves with pump power.

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Excimer laser로 재결정화한 LDD구조의 poly-Si TFT 제작 (Fabrication of the LDD Structure poly-Si TFT with Excimer Laser Recrystallization Process)

  • 정준호;박용해
    • 전자공학회논문지A
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    • 제32A권2호
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    • pp.324-331
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    • 1995
  • The leakage current characteristics of the low temperature processed LDD structure poly-Si TFT is analyzed. The excimer laser technology was applied to the recrystallization process of poly-Si film and the maximum processing temperature was retained under 600.deg.C. From the fabricated LDD space 0.3.mu.m to 3$\mu$m, the best on/off current ration could be obtained with the 1.3$\mu$m LDD space. And the threshold voltage did not increase more than 4V over 0.8$\mu$m LDD space. The characteristics of leakage current was compared to non-LDD structure TFT to analyze the mechanism of leakage current. Consequently, it could be concluded that the leakage current is strongly affected by the trap states as well as high electric field between gate and drain.

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능동-수동 경계에서의 반사가 다전극 DBR 레이저의 튜닝특성에 미치는 영향 (Effect of the reflectance at the active-passive interface on the tuning characteristics of a multielectrode DBR laser)

  • 홍성룡;김덕봉;최안식;윤태훈;김재창;김선호
    • 한국광학회지
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    • 제7권3호
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    • pp.260-265
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    • 1996
  • 본 논문에서는 특성행렬을 사용하여 다전극 DBR 레이저의 능동 영역과 수동 영역의 경계가 튜닝특성에 미치는 영향에 대하여 연구하였다. 능동-수동 경계면에서 굴절율의 변화가 급격한 경우에 경계면에서의 반사가 레이저의 위상특성과 임계이득 특성에 왜곡을 일으켜 연속 튜닝범위가 좁아지게 된다. 반면 완만한 굴절율 변화를 가진 경우에서는 능동-수동 경계의 반사에 의한 영향이 줄어 연속튜닝범위가 넓고 튜닝특성이 일반적인 DBR 레이저의 해석방법(능동-수동 경계를 무시하는 경우)에 의한 튜닝특성과 비슷함을 확인하였다.

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파장가변 Sampled-grating Distributed Bragg Reflector (SG-DBR) 레이저 다이오드 제작 (Fabrication and Characteristics of Tunable Butt-Coupled Sampled-grating Distributed Bragg Reflector (SG-DBR) Laser Diodes)

  • 이지면;오수환;고현성;박문호
    • 한국전기전자재료학회논문지
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    • 제17권1호
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    • pp.16-20
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    • 2004
  • We present the fabrication and performance of wavelength tunable butt coupled (BT) sampled-grating (SG) distributed bragg reflector (DBR) - planar buried heterostructure (PBH) laser diodes (LD). The fabricated LD showed the high optical output power due to the high coupling efficiency between active and passive components by the BT coupling methods. The series resistance and diode ideality factor of LD were measured to be 3.7 $\Omega$ and 1.35, respectively. The average threshold current was 25 ㎃. The output powers of BT-SG DBR-PBH-LD were obtained to be as high as 12.3 and 24.56 ㎽ at 100 and 200 ㎃, respectively. The maximum wavelength tuning range was about 31 nm and the side mode suppression ratio was about 37 dB.

레이저에 의한 포토레지스트의 마스크리스 페터닝 (Maskless patterning of Photoresist by laser)

  • 이경철;김재권;이천;최진호;이강욱;최익순
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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    • pp.886-888
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    • 1998
  • By irradiating photoresist on Si or glass with $Ar^+$ (${\lambda}$=514 nm, CW) and Nd:YAG (${\lambda}$=266 and 532nm, pulse) laser beam, the photoresist was etched masklessly in air. Using a fourth harmonic Nd:YAG laser beam, the etching threshold of energy fluence was $25\;J/cm^2$ and the damage of substrate was appeared over $40\;J/cm^2$.

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Fabrication of excimer laser annealed poly-Si thin film transistor using polymer substrates

  • Kang, Soo-Hee;Kim, Yong-Hoon;Han, Jin-Woo;Seo, Dae-Shik;Han, Jeong-In
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1162-1165
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    • 2006
  • In this paper, the characteristics of polycrystalline silicon thin-film transistors (poly- Si TFTs) fabricated on polymer substrates are investigated. The a-Si films was laser annealed by using a XeCl excimer laser and a four-mask-processed poly-Si TFT was fabricated with fully self-aligned top gate structure. The fabricated nMOS TFT showed field-effect mobility of ${\sim}30\;cm^2/Vs$, on/off ratio of $10^5$ and threshold voltage of 5 V.

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양자선 레이저의 공진기 길이 변화에 따른 시간적 및 공간적 특성 (Cavity-Length-Dependent Spectral and Temporal Characteristics of the Quantum Wire Laser)

  • 최영철;김태근
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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    • pp.1094-1097
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    • 2003
  • In this paper, the cavity-length-dependent spectral and temporal characteristics of a V-groove AlGaAs-GaAs quantum wire (QWR) laser at each subband were investigated. At short cavity lasers less than $300{\mu}m$, a discrete wavelength switching from the n=1 to the n=2 subband occurred due to the increased threshold gain, resulting from the increased cavity loss. Using the characteristic of the wavelength shift from n=1 to the n=2 subband with shortening the cavity length, ultrafast lasing behaviors under gain switching at the n=1 and the n=2 subband transition were demonstrated and compared.

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집적화된 광 싸이리스터와 수직구조 레이저를 이용한 광 로직 AND/OR 게이트에 관한 연구 (Optical AND/OR gates based on monolithically integrated vertical cavity laser with depleted optical thyristor)

  • 김두근;정인일;최영완;최운경
    • 한국정보통신설비학회:학술대회논문집
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    • 한국정보통신설비학회 2006년도 하계학술대회
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    • pp.19-23
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    • 2006
  • Latching optical switches and optical logic gates AND and OR are demonstrated, for the first time, by the monolithic integration of a vertical cavity lasers with depleted optical thyristor structure, which have not only a low threshold current with 0.65 mA. but also a high on/off contrast ratio more than 50 dB. By simple operating technique with changing a reference switching voltage, this single device operates as two logic functions, optical logic AND and OR. The thyristor laser fabricated using the oxidation process achieved a high optical output power efficiency and a high sensitivity to the optical input light.

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CSP-DH 구조 반도체 레이저의 캐리어 확산 방정식을 위한 모델링 (The Carrier Diffusion Modeling of CSP-DH Semiconductor Laser Structures)

  • 이상태;전현성;이찬용;엄금용;윤종욱;윤석범;오환술
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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    • pp.469-471
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    • 1988
  • The basic modeling is analyzed on the optoelectronic properties of CSP-DH laser structure using self-consistent calculation of optical field and the electron-hole distribution in the active region. Laser properties is modelled include gain profile, threshold, near field and far field pattern. This new characterization is allowed for consideration such as carrier spatial hole burning due to strong optical fields which stimulate recombination.

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V형 양자선 레이저의 전류 차단층에 대한 연구 (A Study on Current Blocking Configuration of V-Groove Quantum Wire Laser)

  • 조태호;김태근
    • 한국전기전자재료학회논문지
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    • 제16권12S호
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    • pp.1268-1272
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    • 2003
  • In order to enhance current Injection efficiency of Y-groove inner strife(VIS) quantum wire lasers, three different current configurations, n-blocking on p-substrate(VIPS), p-n-p-n blocking on n-substrate(VI(PN)nS), p-blocking on n-substrate(VINS) have been designed and fabricated. Among them VIPS laser showed the most stable characteristics of lasing up to 5 mW/facet, a threshold current of 39.9 mA at 818 nm, and an external differential quantum efficiency of 24 %/facet. The current tuning rate was almost linear 0.031 nm/mA, and the temperature tuning rate was measured to be 0.14 nm/$^{\circ}C$.