• Title/Summary/Keyword: Optical amplifiers

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A Study on Design and Manufacture of an Inchworm Linear Motor System (인치웜 리니어 모터 시스템 설계 및 제작에 관한 연구)

  • Ye Sang Don;Jeong Jae Hoon;Min Byeong Hyeon
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.12
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    • pp.174-181
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    • 2004
  • Ultra precision positioning mechanism has widely been used on semiconductor manufacturing equipments, optical spectrum analyzer and cell manipulations. Ultra precision positioning mechanism is consisted of several actuators, sensors, guides and control systems. Its efficiency depends on each performance of components. The object of this study is to design, analysis and manufacture all of the inchworm linear motor system, which is one of the equipments embodied in ultra precision positioning mechanism. Inchworm linear motor system is consisted of a controller system and an inchworm linear motor, and its driving form is similar to a motion of spanworm. A design and manufacture of inchworm linear motor, which is consisted of three PZT actuators, a rod, two columns and a guide plate, are performed. Minimizing the von-Mises stress of the hinge using Taguchi method and simulation by FEM software optimizes the structural design in a column of flexure hinge. The designed columns and guide plates are manufactured by a W-EDM and NC-milling. A controller system, which is an apparatus to drive inchworm linear motor, can easily adjust driving conditions by varying resonance frequency and input-output voltage of actuators and amplifiers. The performance of manufactured inchworm linear motor system is verified and valuated. In the future, inchworm linear motor system will be used to make a more precision positioning by reinforcing a sensor and feedback system.

Development of a Low Frequency Accelerometer using the Fiber Bragg Grating Sensor (Fiber Bragg Grating 센서를 이용한 저진동 가속도계 개발)

  • Pack, In-Seok;Kang, Han-Bin;Lee, Kye-Kwang;Lee, Seok-Soon
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.10
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    • pp.1101-1109
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    • 2012
  • Accelerometers play a key role in the structural assessment. However, the current electric type accelerometers have certain limitations to apply some structures such as heavy cabling labor, installed sea structure and sensitivity to electromagnetic fields. An optical Fiber Bragg Grating (FBG) accelerometer has many advantages over conventional electrical sensors since their immunity to electromagnetic interference and their capability to transmit signals over long distance without any additional amplifiers, and there is no corrosion from sea water. In this paper, we have developed a new FBG-based accelerometer. The accelerometer consists of two cantilevered type beams and a mass and two rollers. A bragg grating element is not directly glued to a cantilever to avoid possible non-uniform strain in the element. Instead, the bragg grating element will be attached to rotation part that rolled inducing vertical movement of the mass and support cantilever beams so that the bragg grating element is uniformly tensioned to achieve a constant strain distribution. After manufacturing, we will prove the performance and the natural frequency of the accelerometer through the experiment with a vibration shaker. The FBG-based accelerometer is developed for measuring the vibration not exceeding 50 Hz for the marine and civil structures.

Three-staged amplifier properties of single-short pulsed distributed feedback dye laser using a XeCl laser (XeCl 레이저를 이용한 단일 단펄스 분포궤한 색소레이저의 3단 증폭기 특성)

  • 김성훈;이영우;김용평
    • Korean Journal of Optics and Photonics
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    • v.10 no.5
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    • pp.424-429
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    • 1999
  • The amplifier properties of single distributed feedback dye laser with 106 ps pulse width and 616 nm wavelength were invested using only one XeCl-excimer laser as pump source. For optimized amplification of DFDL, the three-stage amplifiers were arranged with increasing cross-section and accordingly increasing pump energies. The first AmpI, II stages were dye cell of 5 mm, 10 mm and contained a $6{\times}10^{-4}$ [mol/l](solvent : Methanol) of Rhodamine 610. Double-pass amplification in the AmPII was measured to suppress the ASE by using a diffraction grating. The beam intensity of AmpI, II was saturated with a gain of respectively 10 and 48. The last AmpIII was Bethune cell of 30 mm and contained a $3{\times}10^ {-4}$ [mol/l] (solvent : Ethanol) of Rhodamine 610. In the single-pass and double-pass amplification, the output energy was obtained 168.2 $\mu$J and 471$\mu$J respectively.

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Scanning Acoustic Microsope System Using 200MHZ ZnO Transducer (ZnO를 이용한 초음파 현미경의 제작과 평가)

  • Jang, Ji-Won;Do, Si-Hong;Lee, Jong-Gyu
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.25 no.4
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    • pp.200-208
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    • 1989
  • To the purpose of preparation for investigating aspect of material that not revealed by the light microscope and extending our knowledge in applicable field, a scanning acoustic microscope system of 200MHz was organized and appraised its performance with experiments. Professor N.CHUBACHI in Tohoku University in Sendai, Japan provided the ZnO transducer with lens. The system for transmitting and receiving ultrasonic pulses of 200nsec was organized with a rectangular audio wave generator for modulation of 200MHz carrier wave, gating system for transmitting and receiving, mixer for converting intermediate frequency, a directional coupler, ZnO transducer, radio frequency amplifiers. detecter and personal computer. The Scanning system was driven in micro steps with three stepping motors in the direction of x, y and z axes. The system was a reflecting type scanning acoustic microscope and the operation program processed graphics data from receiving echo intensities. Photograph of fish scale obtained by optical microscope was compared with its image by the scanning acoustic microscope organized here. The result was satisfiable.

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Proposal and Implementation of 2-D OCDMA System with Reconfigurable Array Encoder/Decoder and Double Hard Limiters (배열형 가변 부호기/복호기와 이중 하드 리미터를 적용한 2-D OCDMA시스템 제안 및 구현)

  • 김진석;김범주;권순영;박종대
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.7A
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    • pp.705-711
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    • 2004
  • We propose novel OCDMA system with the structure of reconfigurable may encoder/decoder(RAE/ RAD), which are able to reallocate the 2-D optical codes to each subscriber and recover the transmitted data at all the receiving nodes. We have first implemented the double hard limiters composed of limiting amplifier(first hard limiter) that maintain a level of the encoded data from receiving node and AND detector(second hard limiter) for detecting the position of the encoded data and recovering the data. With the proposed system, it was successfully implemented to recover a specific channel data out of 16 code-multiplxed channels using FPGA and 4 DFB-LDs having distinct wavelengths. From experimental results, the code length resulted from increasing the number of the simultaneously connected channels has been reduced by using 2-D OCDMA multiplexed in time and wavelength instead of 1-D OCDMA. In addition, bit errors phenomenon on account of deterioration of autocorrelation peak-to-side lobe ratio is enhanced by using the double hard limiters composed of AND detector and limiting amplifiers.

Ho3+-Doped Amorphous Dielectrics:Emission and Excitation Spectra of the 1.6 μm Fluorescence (Ho3+ 첨가 비정질 유전체 : 1.6μm 헝광의 방출 및 여기 스펙트럼)

  • 최용규
    • Journal of the Korean Ceramic Society
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    • v.41 no.8
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    • pp.618-622
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    • 2004
  • Excitation spectra of the 1.6 rm emission originating from $Ho^{3+}$$^{5}$ I$_{5}$ \longrightarrow$^{5}$ I$_{7}$ transition in fluoride, sulfide, and selenide glasses were measured at wavelengths around 900nm where the fluorescing $^{5}$ I$_{5}$ level is located. In specific energy range where the frequency upconversion populating $^{5}$ F$_{1}$ state happens, the excitation efficiency of the 1.6 fm emission was deteriorated in fluoride and sulfide hosts. In selenide however spectral line shapes of the excitation spectrum and the '$^{5}$ I$_{8}$ \longrightarrow$^{5}$ I$_{5}$ absorption spectrum looked seemingly identical to each other. Differences in optical nonlinearity as well as electronic band gap energy of the host glasses used are responsible for the experimental observations. On the other hand, codoping of rare earths such as Tb$^{3+}$, Dy$^{3+}$, Eu$^{3+}$, and Nd$^{3+}$ was effective in decreasint the terminating $^{5}$ I$_{7}$ level lifetime. However, at the same time, some of the codopants increased unnecessary absorption at the 1.6 $\mu$m wavelengths via their ground state absorption. Though the lifetime quenching effect of Eu$^{3+}$ was moderate, it exhibited no additional extrinsic absorption at the 1.6 $\mu$m band.EX>m band.