1. Articles from Hwi Don Lee

    1-6 of 6
    1. Akinetic swept-source optical coherence tomography based on a pulse-modulated active mode locking fiber laser for human retinal imaging

      Akinetic swept-source optical coherence tomography based on a pulse-modulated active mode locking fiber laser for human retinal imaging

      Optical coherence tomography (OCT) is a noninvasive imaging modality that can provide high-resolution, cross-sectional images of tissues. Especially in retinal imaging, OCT has become one of the most valuable imaging tools for diagnosing eye diseases. Considering the scattering and absorption properties of the eye, the 1000-nm OCT system is preferred for retinal imaging. In this study, we describe the use of an akinetic swept-source OCT system based on a pulse-modulated active mode locking (AML) fiber laser at a 1080-nm wavelength for in-vivo human retinal imaging. The akinetic AML wavelength-swept fiber laser was constructed with polarization-maintaining fiber that has an average ...

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    2. A Fiber Bragg Grating Sensor Interrogation System Based on a Linearly Wavelength-Swept Thermo-Optic Laser Chip

      A Fiber Bragg Grating Sensor Interrogation System Based on a Linearly Wavelength-Swept Thermo-Optic Laser Chip

      A linearized wavelength-swept thermo-optic laser chip was applied to demonstrate a fiber Bragg grating (FBG) sensor interrogation system. A broad tuning range of 11.8 nm was periodically obtained from the laser chip for a sweep rate of 16 Hz. To measure the linear time response of the reflection signal from the FBG sensor, a programmed driving signal was directly applied to the wavelength-swept laser chip. The linear wavelength response of the applied strain was clearly extracted with an R-squared value of 0.99994. To test the feasibility of the system for dynamic measurements, the dynamic strain was successfully interrogated ...

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    3. Short cavity active mode locking fiber laser for optical sensing and imaging

      Short cavity active mode locking fiber laser for optical sensing and imaging

      We demonstrate a highly linear wavenumber- swept active mode locking (AML) fiber laser for optical sensing and imaging without any wavenumber-space resampling process. In this all-electric AML wavenumber-swept mechanism, a conventional wavelength selection filter is eliminated and, instead, the suitable programmed electric modulation signal is directly applied to the gain medium. Various types of wavenumber (or wavelength) tunings can be implemented because of the filter-less cavity configuration. Therefore, we successfully demonstrate a linearly wavenumber-swept AML fiber laser with 26.5 mW of output power to obtain an in-vivo OCT image at the 100 kHz swept rate.

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    4. Simultaneous Dual-Band Wavelength-Swept Fiber Laser Based on Active Mode Locking

      Simultaneous Dual-Band Wavelength-Swept Fiber Laser Based on Active Mode Locking

      We report a simultaneous dual-band wavelength-swept laser based on the active mode locking method. By applying a single modulation signal, synchronized sweeping of two lasing-wavelengths is demonstrated without the use of a mechanical wavelength-selecting filter. Two free spectral ranges are independently controlled with a dual path-length configuration of a laser cavity. The static and dynamic performances of a dual-band wavelength-swept active mode locking fiber laser are characterized in both the time and wavelength regions. Two lasing wavelengths were swept simultaneously from 1263.0 to 1333.3 nm for the 1310 nm band and from 1493 to 1563.3 nm for ...

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    5. Optical Coherence Tomography Using Active MODE-LOCKING Fiber Laser

      Optical Coherence Tomography Using Active MODE-LOCKING Fiber Laser

      Discloses is an optical coherence tomography (OCT) which uses an active mode-locking fiber laser in order to obtain image information of a sample. An imaging device in accordance with an embodiment comprises: a light source unit; a light separation unit; a reference unit; a diagnostic unit; a light coupling unit; and a signal processing unit. The imaging device removes a high-priced variable filter which has mechanical restrictions by directly delivering a modulation signal to a light source unit, so it can overcome mechanical restrictions and reduce costs.

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    6. Characterization of wavelength-swept active mode locking fiber laser based on reflective semiconductor optical amplifier

      Characterization of wavelength-swept active mode locking fiber laser based on reflective semiconductor optical amplifier

      The static and dynamic characteristics of a wavelength-swept active mode locking (AML) fiber laser are presented in both the time-region and wavelength-region. This paper shows experimentally that the linewidth of a laser spectrum and the bandwidth of the sweeping wavelength are dependent directly on the length and dispersion of the fiber cavity as well as the modulation frequency and sweeping rate under the mode-locking condition. To achieve a narrower linewidth, a longer length and higher dispersion of the fiber cavity as well as a higher order mode locking condition are required simultaneously. For a broader bandwidth, a lower order of ...

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    1-6 of 6
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  2. Topics in the News

    1. (6 articles) Pusan National University
    2. (6 articles) Hwi Don Lee
    3. (5 articles) Myung Yung Jeong
    4. (5 articles) Chang-Seok Kim
    5. (2 articles) Jun Geun Shin
    6. (2 articles) Tae Joong Eom
    7. (1 articles) UC Irvine
    8. (1 articles) Gwangju Institute of Science and Technology
    9. (1 articles) Byeong Ha Lee
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    Characterization of wavelength-swept active mode locking fiber laser based on reflective semiconductor optical amplifier Optical Coherence Tomography Using Active MODE-LOCKING Fiber Laser Simultaneous Dual-Band Wavelength-Swept Fiber Laser Based on Active Mode Locking Short cavity active mode locking fiber laser for optical sensing and imaging A Fiber Bragg Grating Sensor Interrogation System Based on a Linearly Wavelength-Swept Thermo-Optic Laser Chip Akinetic swept-source optical coherence tomography based on a pulse-modulated active mode locking fiber laser for human retinal imaging Intravascular Imaging-Guided Percutaneous Coronary Intervention: A Universal Approach for Optimization of Stent Implantation Clinical Usefulness of a Novel Optical Coherence Tomography Procedure, “Low Molecular Weight Dextran Infusion Followed by Catheter PUSH (D-PUSH)” Optical Coherence Tomography to Guide Percutaneous Coronary Intervention of the Left Main Coronary Artery: the LEMON study Impact of optical coherence tomography findings on clinical outcomes in ST-segment elevation myocardial infarction patients: a MATRIX (Minimizing Adverse Hemorrhagic Events by Trans-radial Access Site and angioX) OCT sub-study OCTA Multilayer and Multisector Peripapillary Microvascular Modeling for Diagnosing and Staging of Glaucoma Optical coherence tomography angiography for identifying choroidal neovascular membranes: a masked study in clinical practice