• Title, Summary, Keyword: External cavity laser

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External Cavity Laser with a Tunable Chirped Fiber Bragg Grating for Adjusting the Number of Longitudinal Laser Mode (외부 공진기 레이저의 발진 모드 수 조절에 관한 연구)

  • Yook, Tae-Kyung;Lee, Kyung-Shik;Park, Manh-Yong;Kim, Byoung-Whi
    • Korean Journal of Optics and Photonics
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    • v.16 no.5
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    • pp.406-410
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    • 2005
  • we propose an external cavity laser which can adjust the number of longitudinal laser mode by using a tunable chirped fiber. Bragg grating. By inducing a tunable temperature gradient in a uniform fiber Bragg grating, the bandwidth of the unform fiber Bragg grating can be tuned. With the chirped fiber Bragg grating as an external reflector of the external cavity laser, the number of longitudinal laser mode was able to be tuned from one to two or three modes.

Characteristics of an External-Cavity Semiconductor Laser with a Fabry-Perrot Etalon inside the External reflector (외부공진기 내에 훼브리 페롯 에탈론이 삽입된 반도체 레이저의 특성)

  • 이명우;서동선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.6
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    • pp.793-801
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    • 1993
  • We show theoretically that the performance characteristics of an external cavity semiconductor laser, such as frequency locking and frequency noise reduction, can be greatly improved by just inserting a high finesse Fabry-Perrot(F-P) etalon inside the external reflector. For example, when the F-P etalon of finesse 30 and optical thickness 1.5cm is inserted inside the external cavity of length 3.0cm, the frequency locking accuracy and the linewidth reduction ration are increased up to 7.6 times and 86 times respectively compared with the conventional external-cavity laser under the same operation condition.

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Fabrication of the Single-Mode External-Cavity Laser using Micro Block Stacking Technique (Micro Block Stacking 방법으로 제작한 집적형 단일모드 외부 공진 레이저)

  • Yoon, Hyun-Jae
    • Korean Journal of Optics and Photonics
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    • v.19 no.2
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    • pp.140-143
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    • 2008
  • The integrated external cavity laser has been fabricated with a 1550 nm FP-LD, an optical filter, a micro ball lens and accurate ceramic blocks using a micro-block stacking (MBS) technique. The integrated external cavity laser module whose size is only $2.0{\times}2.1{\times}0.7\;mm^3$ has been mounted on the TO-CAN package. For the case of the 1.8% transmission filter, the single mode characteristic has been obtained with the optical power of -27.1 dBm and the SMSR of 31.7 dB.

Integrated Cavity Output Spectroscopy Using an External Cavity Diode Laser for the Density Absorption Measurement of Trace Gases (미량 기체의 밀도 측정을 위한 외부 공진기 반도체 레이저 광학공동 적분 투과 분광법)

  • Ryoo Hoon Chul;Yoo Yong Shin;Lee Jae Yong;Hahn Jae Won
    • Journal of the Korean Vacuum Society
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    • v.15 no.1
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    • pp.24-30
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    • 2006
  • Integrated cavity output spectroscopy(ICOS) is a simple, non-intrusive absorption measurement technique that can detect and quantify trace-level gas species. The spectral absorbance of a gas is quantified from the integrated optical output of the modulated high-finesse cavity containing the sample which is irradiated by a wavelength-swept laser source. We constructed an experimental setup by using a tunable single mode external cavity diode laser operating at the wavelength near 765 nm and a Fabry-Perot cavity with length modulation achieved by a piezoelectric transducer where one of the cavity mirrors sat on. In the experiment performed on minute oxygen gas at the wave-length near 764.5nm, we demonstrated the minimum detectable absorption of $8.45\times10^{-8}cm^{-1}$.

Beat Frequency Switchable Dual-mode External cavity laser (비트 주파수를 스위칭할 수 있는 듀얼 모드 외부 공진기 레이저)

  • Kim, Chul-Seop;Kim, Ryun-Kyung;Lee, Kyung-Shik;Song, Jeong-Hwan;Oh, Yun-Kyung
    • Korean Journal of Optics and Photonics
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    • v.17 no.6
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    • pp.489-492
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    • 2006
  • We demonstrate a beat frequency-Switchable dual-mode external cavity laser hybrid integrated on planar lightwave circuit with an FP-LD and a sampled grating as external reflector. The dual-mode external avity laser was able to switch its beat frequency from 132GHz to 406GHz by changing LD current from 50mA to 55mA.

Real-time Subtle Vibration Sensing of Optical Fiber Cable based on External-cavity Frequency-swept Laser (외부공진형 광주파수가변 레이저를 이용한 실시간 광섬유 케이블의 미세 진동 측정 연구)

  • Jang, Hansol;Kim, Chang-Seok
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.6_2
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    • pp.943-948
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    • 2020
  • In this paper, we developed a fiber optic interferometer system based on frequency-swept laser. This frequency-swept laser with an external-cavity structure can generate a high coherent light with a linewidth of 132 kHz at 1552 nm. It also shows a superior swept linearity of R2 = 0.99995 under repetition rate of 200 kHz due to absence of mechanical moving parts in the laser cavity. By using a piezoelectric fiber optic stretcher, various vibration experiments were implemented, such as 0.5 to 2.0 kHz vibration signals with intervals of 0.5 kHz, with a sampling rate of 7 kHz. Real-time peak tracking can be successfully recovered according to the applied vibration frequency with high linearity of R2 = 0.99983.

External Cavity Lasers Composed of Higher Order Gratings and SLDs Integrated on PLC Platform

  • Shin, Jang-Uk;Oh, Su-Hwan;Park, Yoon-Jung;Park, Sang-Ho;Han, Young-Tak;Sung, Hee-Kyung;Oh, Kwang-Ryong
    • ETRI Journal
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    • v.29 no.4
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    • pp.452-456
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    • 2007
  • Very compact 4-channel 200-GHz-spacing external cavity lasers (ECLs) were fabricated by hybrid integration of reflection gratings and superluminescent laser diodes on a planar lightwave circuit chip. The fifth-order gratings as reflection gratings were formed using a conventional contact-mask photo-lithography process to achieve low-cost fabrication. The lasing wavelength of the fabricated ECLs matched the ITU grid with an accuracy of ${\pm}0.1$ nm, and optical powers were more than 0.4 mW at the injection current of 80 mA for all channels. The ECLs showed single mode operations with more than 30 dB side lobe suppression.

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A Study on the Construction of Littman and Littrow Type Tunable Diode Laser Systems (Littman 및 Littrow 타입 파장가변 반도체 레이저의 제작에 관한 연구)

  • Baek, Woon-Sik
    • Korean Journal of Optics and Photonics
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    • v.17 no.3
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    • pp.273-277
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    • 2006
  • In this paper, we constructed the Littman type and fixed Littrow type tunable external-cavity diode laser systems. The laser output, which is the 0th-order diffracted beam from the diffraction grating in an external cavity, was the single longitudinal mode. Its FWHM was measured as less than 9MHz. With the diode driving current of 140mA and operating temperature of $25^{\circ}C$, the coarse tuning range of 5.375nm was measured for the Littman type, and of 13.65nm was measured for the fixed Littrow type. A fine tuning experiment in which an external mirror was rotated by a PZT driven by a sawtooth wave was performed, and its tuning range of 0.042nm was measured for both types. The fixed Littrow type tunable external-cavity diode laser system was an improvement on the conventional Littrow type tunable laser system in which the output direction varies due to the grating embedded in the mirror plate.

Second Harmonic Generation with a Type II Phase-Matched $KTiOPO_4$ and an External Ring Cavity (제2종 위상정합용 $KTiOPO_4$와 고리형 공동을 이용한 제2고조파 발진)

  • 김경범;박주현;노재우
    • Korean Journal of Optics and Photonics
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    • v.9 no.4
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    • pp.236-239
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    • 1998
  • We constructed a frequency doubler with a frequency-stabilized Nd:YAG Laser, a nonlinear crystal KTP, and an external resonant cavity. Using type II phase-making method and a resonant cavity, one usually have a serious problem that the second harmonic conversion efficiency is decreased greatly, for under usual circumstances ordinary ray and extraorninary ray cannot be resonated in a cavity simultaneously. With the change of temperature and incident angle of KTP, we found an optimized condition for the phase-matching and double-resonance. As a result we produced 26 mW of green light with 318 mW of fundamental laser power from a cw Nd:YAG laser.

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