• Title/Summary/Keyword: Tunable 필터

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Measurement of Hysteresis in PZT-Type Tunable Filters Utilizing OFDR (OFDR을 이용한 PZT형 파장가변 필터의 이력 측정)

  • Park, Do-Hyun;Yeh, Yun-Hae
    • Korean Journal of Optics and Photonics
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    • v.19 no.1
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    • pp.36-42
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    • 2008
  • Implementation of a wavelength-swept source with constant tuning rate adopting a PZT-type tunable filter, requires the knowledge of hysteresis of the filter used. The hysteresis must be considered to avoid any degradation in resolution of the optical frequency domain reflectometry (OFDR) system. An optical spectrum analyzer (OSA) could be used to do the hysteresis measurement, but its measurement time is too long for the high-speed driving conditions for the filter. We proposed a new hysteresis measurement method based on OFDR, which could measure the hysteresis in a real driving condition. A hysteresis measurement apparatus consisted of wavelength-swept source, interferometer, signal processing unit, and PC program is built and used to do the measurement. It is concluded that the new method is useful in the measurement of hysteresis at real driving conditions by successfully implementing a swept-wavelength source whose wavelength change is linear in time.

Tunable fiber interference filter for sensors and communication system (파장가변 광섬유 간섭형 필터 연구개발)

  • 예윤해;윤지옥;이성필
    • Korean Journal of Optics and Photonics
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    • v.9 no.3
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    • pp.151-155
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    • 1998
  • A new Fabry-Perot tunable filter has been built with simple construction, which does not require any additional aligning and/or beam-confining components for the reduction of the diffraction loss. For this feature, one of the two fibers for the filter is processed to have a concave mirror whose curvature is the same as that of the wavefront of the Gaussian beam from the first fiber. After high reflection coatings, the two fibers are aligned to result in an FP filter whose bandwidth, free spectral range, and insertion loss is 1.47nm, 52nm, 5.6dB respectively.

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Microstrip line tunable phase shifter (마이크로스트립 라인 전압제어 가변 대역통과필터)

  • ;Mai linh
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.05a
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    • pp.227-229
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    • 2002
  • In this paper, we report on a microstrip line voltage controlled tunable bandpass filter. We used the characteristic the relative dielectric constant of thin film ferroelectrics depends on the applied dr voltage. we designed using Au/BSTO/MgO/Au structure. We cascaded many resonators for large furling range sustaining 1 GHz renter frequency, narrow band, low IL ($\leq$4 dB). We could design the BPF of which center frequency is 16 GHz, 1.9 GHz tuning range, the narrow bandwidth within 800 MHz, low insertion loss less than 3 dB by adjusting the gap of 3 cascaded resonators.

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Analysis of Sagnac Loop Band-pass Filter in Incorporating Fiber Bragg Gratings (FBG를 삽입한 사냑 루프 대역 통과 필터의 해석)

  • Jung, Eun-Joo;Jeong, Myung-Yung;Kim, Chang-Seok
    • Korean Journal of Optics and Photonics
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    • v.18 no.2
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    • pp.105-110
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    • 2007
  • A tunable band-pass filter of fiber Bragg gratings incorporating the Sagnac loop interferometer configuration is presented. The proposed band-pass filter with extinction ratio 20 dB has practical advantages in terms of price and performance in comparison with the conventional band-pass filter using a circulator.

Hybrid-integrated Tunable Laser Using Polymer-ring Resonator-based Add/Drop Filter Reflector and Reflective Semiconductor Optical Amplifier (폴리머 링 공진기 기반의 가감필터 반사기와 반사형 반도체 광 증폭기가 하이브리드 집적된 파장 가변 레이저)

  • Lee, Ho;Kim, Gun-Woo;Chung, Young-Chul;Kim, Su-Hyun
    • Korean Journal of Optics and Photonics
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    • v.20 no.4
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    • pp.217-222
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    • 2009
  • In this paper, a low-cost hybrid-integrated tunable laser is realized using a polymer-ring resonator-based add/drop filter reflector and a reflective semiconductor optical amplifier. The add/drop filter reflector, composed of a double-ring resonator with different radii, can have characteristics of selective wavelength reflection and wide wavelength tuning with an aid of vernier effect derived from the radii difference. By hybrid-integrating the reflective semiconductor optical amplifier with the add/drop filter reflector, a tunable laser can be realized through an active alignment method. The hybrid laser exhibited a single mode lasing with side mode suppression ratio of 26 dB and full width half maximum of 0.03 nm. In addition, applying a low current as small as 25 mA onto electrodes over add/drop filter reflector, a wavelength tuning range of 17 nm could be obtained.

Widely Tunable Double-Ring-Resonator Add/Drop Filter (광대역 파장가변 이중 링 공진기 Add/Drop 필터)

  • Lee, Dong-Hyun;Lee, Tae-Hyung;Park, Joon-Oh;Kim, Su-Hyun;Chung, Young-Chul
    • Korean Journal of Optics and Photonics
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    • v.18 no.3
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    • pp.216-220
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    • 2007
  • A widely tunable add/drop filter composed of double ring resonators is implemented with high-index-contrast polymer waveguide. To enhance the productivity, directional couplers are designed to have good fabrication tolerance. The refractive indices of the core and cladding in the 1550 nm wavelength are 1.51 and 1.378, respectively. Drop response in comparison with neighborhood peak gets enhanced by more than 2.9 dB at the wavelength where both rings resonate. This filter can be used to build widely tunable laser diode through hybrid-integration with reflective SOA.

Thermo-Optically Tunable Filter Using Evanescent Field Coupling Between Side-Polished Polarization Maintaining Fiber and Polymer Planar Waveguide (측면 연마된 편광유지 광섬유와 폴리머 평면도파로 사이의 소산장 결합을 이용한 열 광학 가변 필터)

  • 윤대성;김광택
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.2
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    • pp.33-38
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    • 2004
  • We have demonstrated a tunable Inter based on an asymmetric directional coupler made of a side-polished polarization maintaining fiber coupled with a polymer planar waveguide. The thermo-optic effects of the polymer planar waveguide induced by a micro-strip heater placed on the top layer of the device leads to shift of resonance wavelength of the coupler. The fabricated device exhibited wide tunable range exceeding 230 nm with 720 ㎽ of applied electrical power.

Thermo-Optic Tunable Filter and Packaging for Micro-Optical Bench (열광학 효과를 이용한 파장 가변 필터와 미세광학벤치를 이용한 패키징)

  • 박헌용;황병철;이승걸;오범환;이일항;박세근
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.203-206
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    • 2003
  • Thermo-optic tunable filter, with 4-pairs of H/L layers for DBR, was designed and fabricated. The transmittance characteristics of the filter were measured. Additionally, heating system and temperature sensor system were used in order to observe property of the filter by thermo-optic effect. The tuning efficiency of the filter was measured to be 0.144nm/K$^{-1}$ showing the tuning range of 9.4nm for the temperature variation of 64.7$^{\circ}C$. Filter, lens and fiber were aligned by micro-optical bench.

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High-Temperature Characteristics of Tunable All-optical Filter Using Fiber Bragg Grating (FBG를 이용한 파장가변 형 전광필터의 고온 특성)

  • Son, Yong-Hwan;Won, Yong-Yuk;Han, Sang-Kook
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.483-484
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    • 2008
  • In this paper, we present high-temperature characteristics of tunable all-optic filter using fiber Bragg grating(FBG), including peak reflectivity, FWHM bandwidth, refractive index change along temperature variation. The characteristics of a FBG tunable filter with refractive index change is affected by its thermal stability.

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Acousto-Optic Wavelength-Tunable Bandpass Filter (음향광학 파장가변 대역투과 필터)

  • 이명수;황인각;김병윤
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.08a
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    • pp.146-147
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    • 2000
  • 광 대역투과 필터$^{(1)(2)}$ 는 WDM 광통신 시스템에서의 채널 선별에 사용되거나 좁은 선폭의 광원을 제작하는 데 사용된다. 또한 광원의 파장을 분석하는 광스펙트럼 분석기나 광섬유 센서 시스템에서 신호처리용 파장 필터 등으로도 널리 쓰이고 있는 중요한 광소자 중에 하나이다. 본 연구에서는 코어 모드감쇠기와 음향광학 가변 필터$^{(3)}$ 를 사용하여 새로운 전광섬유 형태의 광 대역투과 필터를 구현하였다. 본 광 대역투과 필터는 필터의 중심 파장 및 필터의 투과율을 전기적으로 쉽고 빠르게 제어할 수 있다는 장점을 가지고 있다. (중략)

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