• Title/Summary/Keyword: Diode Laser Sensor

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Application of DFB Diode Laser Sensor to Reacting Flow (I) - Estimation and Application to Laminar Flames -

  • Park, Gyung-Min;Masashi Katsuki;Kim, Duck-Jool
    • Journal of Mechanical Science and Technology
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    • v.16 no.11
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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.

Diode-Laser Absorption Sensors for measurement of combustion Gas (연소배기 가스의 계측을 위한 다이오드 레이저 센서)

  • Shin, Myung-Chul;Kim, Se-Won;Kim, Dong-Hyuck
    • Journal of the Korean Society of Combustion
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    • v.11 no.3
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    • pp.26-35
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    • 2006
  • This work forcus on the development of gas sensor that measure the concentrations of exhaust gas using diode laser, Each diode laser for exhaust gas measurement is set to work at near-IR using both DA and WMS methods. Also use of fiber-coupled optical elements makes such a sensor rugged and easy to align. The results showed that gas concentrations of $O_2$, CO, $CO_2$, NO are accurately measured within ${\pm}2%$ error. The application of WMS method increased the beam intensity 2-3 times higher than DA method. It were experimentally compared WMS (Wavelength Modulation Spectroscopy) with DA (Direct Absorption) for the accuracy.

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Temperature measurement of the spray flame using micro scale absorption bands and line strength (마이크로 스케일의 흡수선과 흡수강도를 이용한 분무화염의 온도측정)

  • Choi, G.M.
    • Journal of ILASS-Korea
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    • v.7 no.2
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    • pp.1-6
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    • 2002
  • It is necessary to develope a high frequency diode laser sensor system based on the absorption spectroscopy for the measurement of temperature of the spray flame. DFB diode laser operating near $2.0{\mu}m$ was used to scan over selected $H_2O$ transitions near $1.9{\mu}m\;and\;2.2{\mu}m$, respectively. The measurement sensitivity at wide range of sweep frequency was evaluated using multi-pass cell containing $CO_2$ gas. This diode laser absorption sensor with high temporal resolution up to 10kHz was applied to measure the gas temperature in the spray flame region of liquid-gas 2-phase counter flow flame. The successful demonstration of time series temperature measurement in the spray flame gives us motivation of trying to establish non-intrusive temperature measurement method in the practical spray flame.

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Performance Evaluation according to Optical Power of Laser Diode of Optical Fiber Displacement Sensor for Monitoring High Speed Spindle. (고속주축 모니터링용 광파이버 변위센서의 레이저 다이오드 출력에 따른 성능평가)

  • 박찬규;신우철;홍준희;이동주
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.376-380
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    • 2004
  • This paper is to develop an optical ruer displacement sensor for monitoring high speed spindle. Proper magnitude of optical power as well as amplification of output signal are necessary to improve sensitivity of the sensor. In this paper, to meet the need of improvement of the sensor resolution, we choose proper optical power and amplification level through speculating on optical power of a laser diode.

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Combustion Diagnostics Method Using Diode Laser Absorption Spectroscopy (다이오드 레이저를 이용한 연소진단기법)

  • Cha, Hak-Joo;Kim, Min-Soo;Shin, Myung-Chul;Kim, Se-Won;Kim, Hyuck-Joo;Han, Jae-Won
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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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.

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A Fiber Laser Spectrometer Demodulation of Fiber Bragg Grating Sensors for Measurement Linearity Enhancement

  • Kim, Hyunjin;Song, Minho
    • Journal of the Optical Society of Korea
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    • v.17 no.4
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    • pp.312-316
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    • 2013
  • A novel fiber-optic sensor system is suggested in which fiber Bragg grating sensors are demodulated by a wavelength-sweeping fiber laser source and a spectrometer. The spectrometer consists of a diffraction grating and a 512-pixel photo-diode array. The reflected Bragg wavelength information is transformed into spatial intensity distribution on the photo-diode array. The peak locations linearly correspond to the Bragg wavelengths, regardless of the nonlinearities in the wavelength tuning mechanism of the fiber laser. The high power density of the fiber laser enables obtaining high signal-to-noise ratio outputs. The improved demodulation characteristics were experimentally demonstrated with a fiber Bragg grating sensor array with 5 gratings. The sensor outputs were in much more linear fashion compared with the conventional tunable band-pass filter demodulation. Also it showed advantages in signal processing, due to the high level of photo-diode array signals, over the broadband light source system, especially in measurement of fast varying dynamic physical quantities.

Implementation of Data Transmission System Using PSD Sensor and Laser Diode Module (PSD 센서와 Laser를 이용한 데이터 전송 시스템 구현)

  • Kim, Myung-Hwan;Ma, Keun-Su;Lee, Jae-Deuk
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.3016-3018
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    • 2005
  • The PSD(Position Sensitive Detector) is a sensor for detecting the position of incident light. Because of its various advantages, it is used for position and angle sensing, optical range finders, laser displacement sensing, and etc. In the previous study of the position finding system, the laser tracking robot is developed. Small data rate and unidirectionality is the characteristics of data communication both DSP-based pan/tilt control board and the robot. If we can transmit data to the target using PSD sensor and laser diode module, there is no need for communication devices such as the bluetooth and wireless module. For this reason, this paper presents the new method for data transmission. Transmit data using RS-232 is modulated by a VTF(Voltage To Frequency) converter The laser diode module transmits the modulated data. And then the PSD sensor receive that data. Demodulation process is accomplished by the system which is consisted with trans-impedance amplifier, FTV(Frequency To Voltage) converter, and etc.

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Measurement of Exhaust Gas Concentration using Wavelength Modulation Spectroscopy (파장 변조 기법을 이용한 연소배기 가스의 계측)

  • Kim, Dong-Hyuck;Kim, Se-Won;Shin, Myung-Chul;Kim, Yong-Mo
    • 한국연소학회:학술대회논문집
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    • 2006.10a
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    • pp.97-103
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    • 2006
  • This work forcus on the development of gas sensor that measure the concentrations of exhaust gas using diode laser. Each diode laser for exhaust gas measurement is set to work at near-IR using both DA and WMS methods. Also use of fiber-coupled optical elements makes such a sensor rugged and easy to align. On-line data acquisition and processing can be performed with a PC running LabVIEW software, and absorption signals are measured simultaneously by multiplexing method. Finally, It were experimentally compared WMS (Wavelength Modulation Spectroscopy) with DA (Direct Absorption) for the accuracy.

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Characteristics of the Laser Displacement Sensor Using Optical Triangulation Method (광삼각법을 이용한 레이저 변위 센서의 특성 연구)

  • Park, Jong-Sung;Jeong, Kyu-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.7
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    • pp.40-50
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    • 1999
  • Recently, a laser displacement sensor is widely used for the manufacturing automation. The sensor is generally composed of a diode laser and a light receiving device. The diode laser emits a laser beam and the receiving device detects the light reflected from the measured object. The object position is obtained based upon triangulation method. As a light receiving device, a PSD is usually utilized since its structure is very simple and rugged and has a high accuracy. Although the theoretical relationship for this sensor had been developed, the characteristics of the sensor have not been much experimentally studied. In this paper, several experimental results will presented. The measurement accuracy is affected by the surface conditions such as the reflectance characteristics, the angle of the object's surface and the laser intensity. In addition, it is found that the PSD and the signal processing circuit have nonlinearities and showed that those nonlinearities can be reduced by controlling the emitting laser intensity.

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Species Concentration Measurement Technique Using Wavelength Modulation Absorption Spectroscopy (파장변조 광흡수 분광법을 이용한 농도 계측 기법)

  • Ahn, J.H.;Kim, Y.M.
    • Journal of ILASS-Korea
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    • v.9 no.4
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    • pp.67-76
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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, reasonable cost, robustness, and ease of use. In addition, diode lasers we 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 develop new gas sensing system and to verify feasibility of this system. Wavelength modulation spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

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