Yoohan Kim - Academia.edu (original) (raw)
Papers by Yoohan Kim
The Korean Physical Society, Feb 1, 2018
14th Pacific Rim Conference on Lasers and Electro-Optics (CLEO PR 2020), 2020
We introduce a thick integrated polarization beam splitter (PBS) based on a bridged directional c... more We introduce a thick integrated polarization beam splitter (PBS) based on a bridged directional coupler (DC) with three planar waveguides of 400-nm-high silicon core layer. Contrary to the conventional thin DC-type PBSs using the cross coupling effect of the TM modes, the thick PBS utilizes the cross coupling effect of TE modes because the effective refractive index of the fundamental TM mode is larger than that of the fundamental TE mode in the single mode condition. At the 1,550 nm wavelength, the peak polarization-extinction-ratios (PERs) of the PBS device are calculated to be 33.81 dB and 41.09 dB for TM and TE modes, respectively, and its corresponding insertion losses (ILs) are 1.58 dB and 0.08 dB when its main input and output waveguide width, a bridge waveguide width, waveguide gap and coupling length are 190 nm, 270 nm, 560 nm, and 32.6 μm, respectively.
2018 23rd Opto-Electronics and Communications Conference (OECC), 2018
Integrated polarization diversity devices, such as polarization beam splitter (PBS), polarization... more Integrated polarization diversity devices, such as polarization beam splitter (PBS), polarization rotator (PR), and polarizer, are very important in silicon (Si)-based photonic integrated circuits (PICs). An integrated PBS based on a Si bridged-waveguide directional coupler, an integrated PR formed with an asymmetric Si waveguide having an internal trench, and an integrated TM-mode pass filter based on one-dimensional photonic crystal waveguide are introduced, and experimentally demonstrated results are reported.
Applied Optics, 2018
We introduce a new method for simultaneously measuring group and phase refractive indices, the di... more We introduce a new method for simultaneously measuring group and phase refractive indices, the dispersion profile, and the physical thickness of transparent plates by using low coherent Fabry-Perot (FP) interferometry without using any mechanical scanning and sample rotation. A broadband infrared light source was used for a fiber-type FP interferometer, and the Fourier transform analysis on the measured interference spectra was performed to determine the refractive indices and thickness of BK7, quartz, and fused silica samples over its wavelength range. The accuracy of the physical thickness of the samples was obtained within an order of 1 μm scale, while that of both the group and the phase refractive indices was within the third decimal point.
Optics Letters, 2018
We demonstrate an integrated polarization beam splitter (PBS) of a simple and compact device geom... more We demonstrate an integrated polarization beam splitter (PBS) of a simple and compact device geometry with high polarization extinction ratios (PERs). A silicon PBS based on a three-waveguide directional coupler is numerically simulated for optimum device parameters, and fabricated experimentally. The measured PER values of the fabricated PBSs are 40.74 dB and 39.01 dB for transverse electric and transverse magnetic modes, respectively, and their corresponding insertion losses are 0.35 dB on average for a coupler length of about 29.4 μm.
New Physics: Sae Mulli, 2018
In heavy-ion collision experiments, many kinds of detectors are used for detecting particles. Esp... more In heavy-ion collision experiments, many kinds of detectors are used for detecting particles. Especially, semiconductor detectors play a important role in determining the position of an incident particle thanks to their excellent position resolution. A charged particle passing through a semiconductor detector makes electron-hole pairs. The pairs go toward the electrodes following the electric field formed inside the detector. The trajectory and the momentum of the particle can be calculated by collecting the electrical signal induced by the movement of the pairs. In this study, we simulated a detector that consisted of p-type silicon pixels attached on an n-type silicon bulk. First we defined the geometrical and the electrical properties of the detector via the Graphical User Interface (GUI) of the simulation and executed the program. Then, a simulation based on the iteration method and the multigrid method was used to calculate the potential and the electric field and to show the signal generated by the passing particle. The simulation was based on the ROOT software developed by the CERN.
The Korean Physical Society, Feb 1, 2018
14th Pacific Rim Conference on Lasers and Electro-Optics (CLEO PR 2020), 2020
We introduce a thick integrated polarization beam splitter (PBS) based on a bridged directional c... more We introduce a thick integrated polarization beam splitter (PBS) based on a bridged directional coupler (DC) with three planar waveguides of 400-nm-high silicon core layer. Contrary to the conventional thin DC-type PBSs using the cross coupling effect of the TM modes, the thick PBS utilizes the cross coupling effect of TE modes because the effective refractive index of the fundamental TM mode is larger than that of the fundamental TE mode in the single mode condition. At the 1,550 nm wavelength, the peak polarization-extinction-ratios (PERs) of the PBS device are calculated to be 33.81 dB and 41.09 dB for TM and TE modes, respectively, and its corresponding insertion losses (ILs) are 1.58 dB and 0.08 dB when its main input and output waveguide width, a bridge waveguide width, waveguide gap and coupling length are 190 nm, 270 nm, 560 nm, and 32.6 μm, respectively.
2018 23rd Opto-Electronics and Communications Conference (OECC), 2018
Integrated polarization diversity devices, such as polarization beam splitter (PBS), polarization... more Integrated polarization diversity devices, such as polarization beam splitter (PBS), polarization rotator (PR), and polarizer, are very important in silicon (Si)-based photonic integrated circuits (PICs). An integrated PBS based on a Si bridged-waveguide directional coupler, an integrated PR formed with an asymmetric Si waveguide having an internal trench, and an integrated TM-mode pass filter based on one-dimensional photonic crystal waveguide are introduced, and experimentally demonstrated results are reported.
Applied Optics, 2018
We introduce a new method for simultaneously measuring group and phase refractive indices, the di... more We introduce a new method for simultaneously measuring group and phase refractive indices, the dispersion profile, and the physical thickness of transparent plates by using low coherent Fabry-Perot (FP) interferometry without using any mechanical scanning and sample rotation. A broadband infrared light source was used for a fiber-type FP interferometer, and the Fourier transform analysis on the measured interference spectra was performed to determine the refractive indices and thickness of BK7, quartz, and fused silica samples over its wavelength range. The accuracy of the physical thickness of the samples was obtained within an order of 1 μm scale, while that of both the group and the phase refractive indices was within the third decimal point.
Optics Letters, 2018
We demonstrate an integrated polarization beam splitter (PBS) of a simple and compact device geom... more We demonstrate an integrated polarization beam splitter (PBS) of a simple and compact device geometry with high polarization extinction ratios (PERs). A silicon PBS based on a three-waveguide directional coupler is numerically simulated for optimum device parameters, and fabricated experimentally. The measured PER values of the fabricated PBSs are 40.74 dB and 39.01 dB for transverse electric and transverse magnetic modes, respectively, and their corresponding insertion losses are 0.35 dB on average for a coupler length of about 29.4 μm.
New Physics: Sae Mulli, 2018
In heavy-ion collision experiments, many kinds of detectors are used for detecting particles. Esp... more In heavy-ion collision experiments, many kinds of detectors are used for detecting particles. Especially, semiconductor detectors play a important role in determining the position of an incident particle thanks to their excellent position resolution. A charged particle passing through a semiconductor detector makes electron-hole pairs. The pairs go toward the electrodes following the electric field formed inside the detector. The trajectory and the momentum of the particle can be calculated by collecting the electrical signal induced by the movement of the pairs. In this study, we simulated a detector that consisted of p-type silicon pixels attached on an n-type silicon bulk. First we defined the geometrical and the electrical properties of the detector via the Graphical User Interface (GUI) of the simulation and executed the program. Then, a simulation based on the iteration method and the multigrid method was used to calculate the potential and the electric field and to show the signal generated by the passing particle. The simulation was based on the ROOT software developed by the CERN.