- 1996 University of Colorado at Boulder (Ph.D.-Physics, Optics)
- 1989 Seoul National University (M.S.-Physics, Optics)
- 1984 Seoul National University (B.S.-Physics)
- 2007 – present Professor
- 2003 – 2007 Associate Professor
- 2000 – 2003 Assistant Professor
- 1999 – 2000 GIST, Research Professor
- 1997 – 1999 Osaka National Research Institute, STA Fellow
- 1997 – 1997 KIST, Research Associate
- 1989 – 1991 Advent Co., Senior Researcher
- 1983 – 1987 LG Cable Laboratory, Researcher
- Fabrication and characterization of fiber gratings (LPG, FBG)
- Sensor and sensor systems based on specialty fiber devices
- Development and modeling of Photonic Crystal Fibers (PCF)
- Optical Coherence Tomography (OCT)
- Fluorescence Spectroscopy
- Digital Hologram Microscopy (DHM)
- Endoscopic MEMS probe for medical applications
- Applied Optics LaboratoryApplied Optics Laboratory started with the study in fiber gratings. With the fiber gratings, we have measured the properties of various fibers and fiber modes. We are struggling to design, fabricate and analyze state-of-the-art fiber gratings for fiber sensor systems. Development and modeling of Photonic Crystal Fibers(PCFs) is also one of the main research fields in our lab. It has newly emerged an application field in dispersion management, super-continuum generation using special nonlinearity. Recently, all-fiber interferometer formed with the PCF was developed in our lab and is expected to be applied to high-precision temperature sensing device. Our research scope has been expanded up to bio-medical optics. We have implemented the Optical Coherence Tomography (OCT) system that makes it possible to realize real-time cross-sectional imaging of a living tissue structure with sub-cellular level. OCT takes advantage of non-invasive, non-contact imaging with high resolution and sensitivity. Now, All fiber OCT, Fourier Domain OCT, Full-Field OCT, Stroboscopic OCT, Digital Hologram Microscopy (DHM) Systems are completely implemented and various biological imaging skills are being demonstrated using whole systems. With the development of fluorescence signal detection technology based on special fiber coupler, it enables to simultaneously obtain auto fluorescence signal and three-dimensional image within bio-samples. This innovative technique has great potential in disease diagnosis as bio-medical application tool.Sensor system based on fiber optic interferometer
A pair of fiber gratings can be interpreted as the simplest interferometer. We are one of the world-leading groups in fabricating and analyzing the multiply cascaded fiber gratings. We have developed their applications as the tools for high-sensitive fiber optic sensors. Wavelength-dependence property of fiber gratings can be applied to measure various physical parameters such as temperature, stain, bending, refractive index, etc with simple method and high accuracy. Up-to-dately, hybrid-structured interferometer based on the combination and deformation skills of special fibers is implemented for various sensing applications.
Photonic crystal fibers (PCF)
Photonic crystal fiber (PCF) is a special fiber which has a bunch of air holes formed along the length of the fiber having a 125mm diameter. In a conventional fiber, the core has slightly higher refractive index than the cladding to give Total Internal Reflection (TIR). Contrary to this, in PCF, the core and cladding are consisted of the same silica but the air holes perform the role of cladding. It has newly emerging applications in dispersion management, supercontinuum generation, special nonlinearity, etc. As one of the pioneering groups in PCF, we are fabricating and modeling various PCFs.
Optical Coherence Tomography (OCT)
Optical imaging techniques have become attractive in bio-medical applications due to their non-invasive imaging capability. Optical coherence tomography (OCT) based on low-coherence interferometry enables to visualize the cross-sectional microstructure of a biological tissue with a resolution of a few μm in real time.
– Fiber-based OCT: compact, low cost, alignment free, endoscopic application
– Lensed-fiber probe: compact sample arm probe for forward and side imaging
– FD-OCT: fast speed imaging, high signal-to-noise ratio, high resolution
– FF-OCT: cellular-level imaging with sub-micron scale without beam scanning
Fluorescence spectroscopy (FS)
Fluorescence spectroscopy is useful technique that can be used to obtain the functional properties such as biochemical changes and morphology of tissues. It is able to be combined with OCT systems to acquire fluorescence signal and structural information at the same time.
– Fiber-based fluorescence probe: flexible catheter for cavities or tubular structures
– DCF-based FS: double channel probe with single DCF and DCF coupler
– Combined OCT-FS system: simultaneous measurement of structural and biochemical information at same position based on DCF, DCF lens and DCF coupler.