• 한국산학기술학회논문지
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• 제7권1호
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• pp.46-51
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• 2006

본 논문은 DFB(Distributed Feed-Back) 구조를 갖고 있는 레이저의 성능을 ASE(Amplified Spontaneous Emission)을 이용하여 예측하고자 한다. 설계 후 제작된 레이저의 구조 파라메터 오차를 파괴적이 방법을 사용하지 않고 문턱전류이하에서 방출되는 ASE 스펙트럼을 통해 예측할 수 있다. ASE 스펙트럼은 격자 주기, 두께, 결합계수, 손실, 유전율 등의 구조 파라메터 정보를 포함하고 있다. 본 논문은 구조 파라메터가 발생시키는 ASE 스펙트럼 발생을 모델링한 후 출력된 스펙트럼을 통해 구조 파라메터를 추출하는 프로그램을 개발하여 시뮬레이션하였다.

• 한국전기전자재료학회논문지
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• 제22권3호
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• pp.248-251
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• 2009

We have investigated the effect of the quality of 1.3 um distributed feed back laser diode (DFB-LD) on the design of anti-reflection (AR) coatings. Optimal condition of AR coating to prevent internal feedback from both facets and reduce the reflection-induced intensity noise of laser diode was simulated with Macleod Simulator. Coating materials used in this work were ${Ti_3}{O_5}$ and $SiO_2$, of which design thickness were 105 nm and 165 nm, respectively. AR coating films were deposited by Ion-Assisted Deposition system. The electrical and optical properties of 1.3 um laser diode were characterized by Bar tester and Chip tester. Threshold current and slop-efficiency of DFB-LD were 27.56 mA 0.302 W/A. Far field pattern and wavelength of DFB-LD were $22.3^{\circ}(Horizontal){\times}24.4^{\circ}$ (Vertical), 1313.8 nm, respectively.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.75-83
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• 2003

Diode laser absorption system is advantageous of their non-invasive nature, fast response time, high sensitivity and real-time measurement capability. Furthermore, recent advances in room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications are enabling combustion diagnostics system based on diode laser absorption spectroscopy. So, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor system are now appearing for a variety of applications. The objective of this research is to take advantage of distributed feed-back diode laser and develope new gas sensing system. It experimentally found out that the wavelength, power characteristics as a function of injection current and temperature. In addition to direct absorption and wavelength modulation spectroscopy have been demonstrated in these experiments and have a bright prospect to this diode laser system.

• 전자공학회논문지A
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• 제32A권1호
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• pp.200-205
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• 1995

The 1st and 2nd-order grating structure for long wavelength DFB(Distributed FeedBack) laser diodes are successfully fabricated on InP substrates by using electron beam lithography and reactive ion etch techniques, and also characterized non-destructively by diffraction analysis without removal of photo-resis layer. A new composite layer made by lifted-off Cr layer on thin SiO2 film is developed and used as an etch mask, because PMMA, the e-beamresist, is unsuitable for reactive ion etch of InP. In addition, it is experimentally confiremed that diffraction analysis makes it possible to predict the grating parameters, and the analysis can be used as a non-destructive on-line test to prevent incomplete gratings from being successively processed.

• Journal of Mechanical Science and Technology
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• 제16권11호
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• pp.1550-1557
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• 2002

Diode laser sensor for measuring gas temperature and species concentration in combustion chamber was developed using 2.0 tim distributed feed back lasers. To evaluate the measurement sensitivity of diode laser sensor system, CO2 survey spectra near 2.0 Um were measured and compared with the calculated one. This diode laser absorption sensor was applied to measure gas temperatures in a premixed flat flame of CH$_4$-air mixture. Experimental results were in good agreement with the values by an R-type thermocouple within 6.12%. In addition, successful demonstration of measurement of gas temperature and species concentration in a soot flame showed the promising possibility of diode laser absorption sensors for practical combustion system with non-intrusive method.

• 한국연소학회지
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• 제9권3호
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• pp.27-35
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, resonable cost, robustness, and ease of use. In addition, diode lasers are fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develope a new gas sensing system and to verify feasibility of this system. Wavelength and power characteristics as a function of injection current and temperature are experimentally found out. Direct absorption spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• 한국진공학회지
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• 제15권3호
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• pp.294-300
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• 2006

금속유기화학증착기 (metal-organic chemical vapor deposition)를 이용하여 분포귀환형 (distributed feed back) InP/InGaAs/InP 회절격자 구조를 제작하고 원자력간현미경 (atomic force microscopy)과 주사전자현미경 (scanning electron microscopy) 실험을 통해 표면 및 단면을 분석하였다. 그 위에 분자선증착기(molecular beam epitaxy)법을 이용하여 자발형성 (self-assembled) InAs/InAlGaAs 양자점 (quantum dot)을 성장하고, 광학적 특성을 온도변화 광여기 발광 (photoluminescence)으로 회절격자 구조 없이 성장한 양자점 시료와 비교 분석하였다. 회절격자의 간격 대비 폭의 비가 약 30%인 InP/InGaAs/InP 회절격자가 제작되었으며, 그 위에 성장된 양자점의 경우 상온 파장이 1605 nm에서 PL이 관찰되었다. 이는 회절격자 없이 같은 조건에서 성장된 시료의 상온 파장인 1587 nm 보다 장파장에서 발광하였으며, 회절격자의 영향으로 양자점 크기가 변하였음을 조사하였다.