• Title, Summary, Keyword: 단일광경로

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Compensations of Polarization Mode Dispersion and Thermal Drift in Optical Coherence Tomography with PZT Optical Delay Lines (광간섭 단층촬영(OCT)용 PZT 광경로 지연기에서의 편광모드 분산 및 열요동 보상)

  • Kim, Young-Kwan;Park, Sung-Jin;Kim, Yong-Pyung
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.547-552
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    • 2005
  • We have fabricated and characterized optical delay lines for optical coherence tomography, which is composed of cylindrical PZT(piezoelectric transducer) and single mode optical fiber. The polarization mode dispersion from the optical delay lines was compensated by the polarization controllers. By applying the duplex optical delay line, we minimized the thermal drift due to optical delay lines and obtained the scan range of 2 times that of a single optical delay line. The OCT system showed resolution of $18.6\pm0.5{\mu}m$, scanning range of 1.68mm, and scanning speed of 360.4mm/s.

Development of single optical axis scanning PIV method (단일 광경로 스캔PIV기법의 개발)

  • Kim Hyoung-Bum;Jeong In-Young;Lee Sang-Hyuk;Ryu Chung-Hwan;Jean Hertzberg
    • 한국가시화정보학회:학술대회논문집
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    • pp.6-10
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    • 2005
  • PIV(Particle image velocimetry) presents the flow velocity of whole flow fields in a fraction of a second. Conventional PIV method uses two optical axis configuration during the image grabbing process. That is, the illumination plane and the recording plane must be parallel. This configuration is very natural to grab the whole field without the image distortion. In the real problem, it is often to meet the situation which this configuration is hard to be fulfilled. In this study, we developed new PIV method which only uses single optical axis to grab the particle images. This new PIV method become possible by utilizing the scanning method similar to echo PIV technique. One particle image of scanning PIV consists of scanned several line images and by repeating this scanning process, two particle images were grabbed and processed to produce the velocity vectors.

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Development of the Scanning PIV Method with Single Optical Axis (단일 광경로 스캐닝 PIV기법 개발)

  • Kim, Hyoung-Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.2
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    • pp.181-187
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    • 2007
  • Conventional PIV method uses two optical axis configuration during the image grabbing process. That is, the illumination plane and the recording plane must be parallel. This configuration is very natural to grab the whole field without the image distortion. In the real problem, it is often to meet the situation when this configuration is hard to be fulfilled. In the present study, the new PIV method which uses only single optical axis to grab the particle images is developed. This new PIV method becomes possible by utilizing the scanning method similar to the echo PIV technique. One particle image of the scanning PIV consists of scanned several line images and by repeating this scanning process, two particle images were grabbed and processed to produce the velocity vectors. An optimization study was performed to find parameters which minimize the measurement errors. The effects of particle diameter, beam overlap ratio and particle number density were investigated.

Optical Coherence Tomography with Sinusoidal-Wave Drive an Optical Delay Line using Piezoelectrics Strecher (정현파로 구동되는 PZT 광경로 지연기를 이용한 광 간섭 단층촬영시스템)

  • Kim, Young-Kwan;Kim, Yong-Pyung
    • Korean Journal of Optics and Photonics
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    • v.18 no.4
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    • pp.274-279
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    • 2007
  • We fabricated and characterized an optical delay line for optical coherence tomography (OCT). The delay line was composed of a cylindrical piezoelectric transduce (PZT) and a single mode optical fiber. The OCT system used a duplex scanning optical delay line which was symmetrically driven in the reference and sample arms. We showed that the sinusoidal-wave was superior to a triangular-wave for driving the optical delay line for scanning depth and repeatability.

A Design of Routing Path and Wavelength Assignment with Minimum Number of Wavelengths in WDM Optical Transport Network (WDM 광전달망에서 최소 파장 수를 갖는 경로설계 및 파장할당)

  • 박구현;우재현
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.8
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    • pp.1883-1892
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    • 1998
  • This paper considers the efficient design of routing path and wavelength assignment asignment in the sigle-hop WDM optical transport networks. The connecton demands between node-pairs are given and a connection must be made by only one lightpath. It is assumed that no wavelength conversion is allowed and the physical topology of the network is given. This paper proposes a method to find the routes of lightpaths and assign wavelengths to the routes, which minimizes the number of total wavelength to satisfy all connection demands. We establish a new optimization model that finds the minimum number of wavelengths. A heuristic algorithm with polynomial iterations is developed for the problem. The algorithm is implemented and applied to the netowrks with real problem size. The results of the application are compared with the commericial optimization solver, GAMS/OSL and Wauters & Demeester [8].

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Single Photon Interference Experiments in a Sagnac-type Mach-Zehnder Interferometer (Sagnac 형태로 변형된 Mach-Zehnder 간섭계를 이용한 단일광자 간섭실험)

  • Um, Jayoon;Kim, Yong Soo;Kim, Heonoh
    • Korean Journal of Optics and Photonics
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    • v.23 no.2
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    • pp.71-76
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    • 2012
  • A Sagnac-type Mach-Zehnder interferometer(SMZI) is a very stable instrument with respect to phase drift because all optical paths can share common optical components. We have observed very stable interference fringes in single photon interference experiments with an extremely attenuated laser beam, and with heralded single photons prepared from polarization correlated photon pairs in type-II spontaneous parametric down-conversion. The phase stability is measured to be about ${\pm}0.18$ rad for the SMZI, in contrast, conventional MZI showed the phase fluctuation of around ${\pm}1.02$ rad.

Fabrication of an On System based on an Optical Delay line with Cylindrical PZT (실린더형 압전소자 광지연선을 이용한 광 간섭형 단층촬영(OCT) 시스템 제작)

  • Park, Sung-Jin;Kim, Young-Kwan;Kim, Yong-Pyung
    • Korean Journal of Optics and Photonics
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    • v.17 no.2
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    • pp.159-164
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    • 2006
  • We demonstrate a compact optical coherence tomography(OCT) system based on the optical fiber delay line controlled by a cylindrical piezo-electric transducer(PZT). An 18-m length of single mode fiber is wrapped under constant tension around a PZT. Approximately 134 windings are used. Wraps of the long length of fiber allow the small expansion of the PZT to be magnified to an optical path length delay of 0.78 m. The OCT system shows characteristics for 2-dimensional imaging, exhibiting 96.9dB of signal-to-noise ratio(SNR), $18.6{\pm}0.5\;{\mu}m$ of axial resolution, and $5\;{\mu}m$ of lateral resolution with samples.

Study on single gap transflective liquid crystal display using the UV Curable Reactive Mesogen (광경화성 고분자를 이용한 단일 갭 반투과형 액정디스플레이 연구)

  • Her, Jung-Hwa;Kim, Jin-Ho;Chin, Mi-Hyung;Lim, Young-Jin;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.293-294
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    • 2009
  • We proposed a novel single gap transflective liquid crystal display (LCD) using liquid crystal with negative dielectric anisotropy. We designed cell structure driven by fringe electric field in the transmissive (T) part and vertical electric field in the reflective (R) part. In the device, high surface pretilt angle of the LC in the R-part is achieved through polymerization of an UV curable reactive mesogen (RM) monomer at surfaces. By optimizing the parameters, a newly developed transflective display has characteristics such as single gap and single gamma curve.

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Synthesis of Polyacrylates Containing Si, Ge and Sn for High Refractive Index (실리콘, 게르마늄, 주석이 결합된 고굴절률 아크릴 고분자의 합성)

  • Maheswara, Muchchintala;Do, Jung-Yun
    • Polymer Korea
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    • v.34 no.6
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    • pp.588-593
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    • 2010
  • New seven acrylic monomers with covalently bonded silicon, germanium, and tin were prepared for high refractive index materials. The monomers were copolymerized with a cross-linkable comonomer (Trimer) to prepare UV-films for optical characterization. The refractive index of the copolymers increased in proportion to the monomer content and extrapolated to determine that of homopolymer. $Ph_3Si$, $Ph_3Ge$, and $Ph_3Sn$ groups contributed to increase the refractive index of acrylic polymer, in which $Ph_3Sn$ was more effective than $Ph_3Ge$. The index increment confidently occurred with $Bu_3Sn$ attachment in comparison with aliphatic acrylic polymers. $Ph_3SnS$-attached acrylate polymer showed a refractive index of 1.671 at 589 nm. The index change was similarly observed at various different wavelengths (656, 830, 1310, and 1550 nm).