Sang-Pil Han - Academia.edu (original) (raw)

Papers by Sang-Pil Han

Journal of Materials Processing Technology, 2004

Asia Communications and Photonics Conference 2015, 2015

Korean Journal of Optics and Photonics, 2014

Active and Passive Optical Components for WDM Communications IV, 2004

Polymer waveguides have attracted a great deal of attention for their potential applications as o... more Polymer waveguides have attracted a great deal of attention for their potential applications as optical components in optical communications, optical interconnections and optical sensors because they are easy to manufacture at a low temperature, and they have a low processing cost. Hot embossing is powerful and effective tools to produce a large volume of waveguides and structure high-precision micro/nano patterns of thin polymer films using a stamp for optical applications. In this work, fabrication techniques of hot embossed polymeric optical waveguides for parallel optical interconnection module, multi-channel variable optical attenuator and optical printed circuit boards are demonstrated. The single- and multi-mode waveguides are produced by core filling and UV curing processes. New approaches to fabricating single-mode polymeric waveguides with the high thermal stability in thermosetting polymers and two-dimensional multi-mode polymeric waveguides for high-density parallel optical interconnections as well as a simultaneous fabrication of single-mode polymeric waveguides with micro pedestals for passive fiber alignment are also reported.

Scientific reports, 2015

Photoconductive antennas with nano-structured electrodes and which show significantly improved pe... more Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources. Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics. However, we discovered that the role of plasmonic field enhancement is limited and near-field distribution of bias field should be considered as well. In this paper, we clearly show that the locally enhanced bias field due to the size effect is much more important than the plasmonic enhanced absorption in the nano-structured electrodes for the THz emitters. Consequently, an improved nano-electrode design is presented by tailoring bias field distribution and plasmonic enhancement. Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT We report a continuously tunable dual-wavelength laser based on the polymer Bragg gratin... more ABSTRACT We report a continuously tunable dual-wavelength laser based on the polymer Bragg gratings for continuous wave terahertz optical beat source generation. The polymer Bragg gratings are used to wavelength selective components in the laser cavity. The measured wavelength tuning range is about 19 nm. The side mode suppression ratio is achieved more than 30 dB for dual wavelength.

Active and Passive Optical Components for WDM Communications V, 2005

A fully optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, w... more A fully optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by an optical slot. We report a 10 Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of the optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT A travelling-wave photomixer was realized. The responsivity was 0.42A/W for 15μm length ... more ABSTRACT A travelling-wave photomixer was realized. The responsivity was 0.42A/W for 15μm length device. It showed a 3dB bandwidth of more than 200GHz, limited by transit-time of photo-generated carriers. Also, it showed a successful THz wave generation up to frequency range of more than 500GHz.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT We characterize InGaAs Schottky barrier diodes (SBDs) with a variation in the anode size... more ABSTRACT We characterize InGaAs Schottky barrier diodes (SBDs) with a variation in the anode size. High-efficiency terahertz (THz) pulse detection of the InGaAs SBDs is performed in the cases of anode diameters of 2 μm and 3 μm. The uniformity of the fabricated 1 × 20 InGaAs SBD array is measured to be fine. The THz imaging results using the 1 × 20 InGaAs SBD array are presented.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT We have investigated the direct modulation characteristics of a phase-shifted 1.3-μm dua... more ABSTRACT We have investigated the direct modulation characteristics of a phase-shifted 1.3-μm dual-mode laser diode. Stable dual-mode operation and high spectral purity are maintained under 2.5-Gbps direct modulation.

2008 International Conference on Photonics in Switching, 2008

ABSTRACT A 10 channel polymer variable optical attenuator array (VOA), which is used for power mo... more ABSTRACT A 10 channel polymer variable optical attenuator array (VOA), which is used for power monitoring and equalization in integrated planar lightwave circuit (iPLC) reconfigurable optical add-drop multiplexer (ROADM) module, is demonstrated. Maximum attenuation of about -41 dB was achieved at very low electrical power of 17 mW and insertion loss was within 0.7~0.9 dB for all channels. Polarization dependent loss for 20 dB attenuation was below 0.5 dB, and adjacent channel crosstalk was less than -40 dB.

35th International Conference on Infrared, Millimeter, and Terahertz Waves, 2010

Abstract We demonstrate a continuous THz emission using a low-temperature-grown InGaAs photomixer... more Abstract We demonstrate a continuous THz emission using a low-temperature-grown InGaAs photomixer and a widely tunable dual-wavelength erbium-doped fiber laser as an optical beat source. The wavelength spacing can be tuned from 2.3 nm to 8.8 nm which ...

Intelligent Systems in Design and Manufacturing VI, 2005

ABSTRACT The performance of data and telecommunication equipment must keep up with the increasing... more ABSTRACT The performance of data and telecommunication equipment must keep up with the increasing network speed. Optical interconnection technology is a promising alternative for high throughput systems. The Optical backplane system was demonstrated with waveguide-embedded optical backplane, transmitter board and receiver board. The transmitter and receiver module were prepared for optical PCB, which consists of the metal optical bench, the driver chips, VCSELs, photodiodes and a tapered polymeric waveguide. And parallel optical transmitter and a receiver module were attached onto the processing boards for the interconnection with optical backplane board. The tapered polymeric waveguides are fabricated using the hot embossing technique. And the propagation loss of the waveguide was approximately 0.1dB/cm at 850nm. The waveguide-embedded optical backplane boards were fabricated by using conventional PCB lamination process. The data transmission characteristics of the processing board have been investigated. In our optical backplane system, we demonstrated up to 10Gb/s 27-1 PRBS NRZ data transmission from the transmitter board to the receiver board through optical backplane. The BERs were less than 10-12 under 8Gb/s data rate, which is sufficient level for telecommunications.

Optics express, Jan 26, 2015

In this study, inspired by the frequency-modulated continuous-wave (FMCW) method, an operation sc... more In this study, inspired by the frequency-modulated continuous-wave (FMCW) method, an operation scheme of continuous-wave (CW) terahertz (THz) homodyne system is proposed and evaluated. For this purpose, we utilized the fast and stable wavelength tuning characteristics of a dual-mode laser (DML) as a beating source. Using the frequency-modulated THz waves generated by DML, a cost-effective and robust operation of CW THz system to be applicable to the measurements of thickness or refractive index of a sample is demonstrated. We believe that the proposed scheme shows a potential to the implementations of compact and fast CW THz measurement systems that can be useful in many THz applications.

Transactions of The Korean Society of Mechanical Engineers A, 2003

2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011

We propose a high-speed frequency-scanning optical beat source using a wavelength swept laser and... more We propose a high-speed frequency-scanning optical beat source using a wavelength swept laser and a tunable laser for continuous THz wave generation. The beat frequency is scanned at 1 kHz over a range with a 2.16 THz width.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT The photomixers enables continuous-wave, frequency-tunable terahertz (THz) emitter and d... more ABSTRACT The photomixers enables continuous-wave, frequency-tunable terahertz (THz) emitter and detector by using conventional photonics technology. To increase the emission and detection efficiency, various antennas have been adopted. In this work, we provide experimental characterizations of various kinds of antenna-integrated photomixers by measuring reference THz pulse from an InAs crystal.

2011 International Conference on Infrared, Millimeter, and Terahertz Waves, 2011

... Phys. Lett. 91, 241102-241104 (2007). [3] N. Kim, YA Leem, JH Shin, CW Lee, SP Han, MY Jeon, ... more ... Phys. Lett. 91, 241102-241104 (2007). [3] N. Kim, YA Leem, JH Shin, CW Lee, SP Han, MY Jeon, DH Lee, DS Yee, SK Noh, and KH Park, “Widely tunable dual-mode multisection laser diode for continuous-wave THz generation,” in Proceedings of 35th international conference ...

2011 International Conference on Infrared, Millimeter, and Terahertz Waves, 2011

We demonstrated a fiber-coupled THz time-domain spectroscopy (TDS) system. A THz output power of ... more We demonstrated a fiber-coupled THz time-domain spectroscopy (TDS) system. A THz output power of 132 nW of the THz emitter in the system was measured by a Golay-cell. Water vapor dips in the free space were clearly observed by the THz detector in the system.

Journal of Materials Processing Technology, 2004

Asia Communications and Photonics Conference 2015, 2015

Korean Journal of Optics and Photonics, 2014

Active and Passive Optical Components for WDM Communications IV, 2004

Polymer waveguides have attracted a great deal of attention for their potential applications as o... more Polymer waveguides have attracted a great deal of attention for their potential applications as optical components in optical communications, optical interconnections and optical sensors because they are easy to manufacture at a low temperature, and they have a low processing cost. Hot embossing is powerful and effective tools to produce a large volume of waveguides and structure high-precision micro/nano patterns of thin polymer films using a stamp for optical applications. In this work, fabrication techniques of hot embossed polymeric optical waveguides for parallel optical interconnection module, multi-channel variable optical attenuator and optical printed circuit boards are demonstrated. The single- and multi-mode waveguides are produced by core filling and UV curing processes. New approaches to fabricating single-mode polymeric waveguides with the high thermal stability in thermosetting polymers and two-dimensional multi-mode polymeric waveguides for high-density parallel optical interconnections as well as a simultaneous fabrication of single-mode polymeric waveguides with micro pedestals for passive fiber alignment are also reported.

Scientific reports, 2015

Photoconductive antennas with nano-structured electrodes and which show significantly improved pe... more Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources. Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics. However, we discovered that the role of plasmonic field enhancement is limited and near-field distribution of bias field should be considered as well. In this paper, we clearly show that the locally enhanced bias field due to the size effect is much more important than the plasmonic enhanced absorption in the nano-structured electrodes for the THz emitters. Consequently, an improved nano-electrode design is presented by tailoring bias field distribution and plasmonic enhancement. Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT We report a continuously tunable dual-wavelength laser based on the polymer Bragg gratin... more ABSTRACT We report a continuously tunable dual-wavelength laser based on the polymer Bragg gratings for continuous wave terahertz optical beat source generation. The polymer Bragg gratings are used to wavelength selective components in the laser cavity. The measured wavelength tuning range is about 19 nm. The side mode suppression ratio is achieved more than 30 dB for dual wavelength.

Active and Passive Optical Components for WDM Communications V, 2005

A fully optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, w... more A fully optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by an optical slot. We report a 10 Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of the optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT A travelling-wave photomixer was realized. The responsivity was 0.42A/W for 15μm length ... more ABSTRACT A travelling-wave photomixer was realized. The responsivity was 0.42A/W for 15μm length device. It showed a 3dB bandwidth of more than 200GHz, limited by transit-time of photo-generated carriers. Also, it showed a successful THz wave generation up to frequency range of more than 500GHz.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT We characterize InGaAs Schottky barrier diodes (SBDs) with a variation in the anode size... more ABSTRACT We characterize InGaAs Schottky barrier diodes (SBDs) with a variation in the anode size. High-efficiency terahertz (THz) pulse detection of the InGaAs SBDs is performed in the cases of anode diameters of 2 μm and 3 μm. The uniformity of the fabricated 1 × 20 InGaAs SBD array is measured to be fine. The THz imaging results using the 1 × 20 InGaAs SBD array are presented.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT We have investigated the direct modulation characteristics of a phase-shifted 1.3-μm dua... more ABSTRACT We have investigated the direct modulation characteristics of a phase-shifted 1.3-μm dual-mode laser diode. Stable dual-mode operation and high spectral purity are maintained under 2.5-Gbps direct modulation.

2008 International Conference on Photonics in Switching, 2008

ABSTRACT A 10 channel polymer variable optical attenuator array (VOA), which is used for power mo... more ABSTRACT A 10 channel polymer variable optical attenuator array (VOA), which is used for power monitoring and equalization in integrated planar lightwave circuit (iPLC) reconfigurable optical add-drop multiplexer (ROADM) module, is demonstrated. Maximum attenuation of about -41 dB was achieved at very low electrical power of 17 mW and insertion loss was within 0.7~0.9 dB for all channels. Polarization dependent loss for 20 dB attenuation was below 0.5 dB, and adjacent channel crosstalk was less than -40 dB.

35th International Conference on Infrared, Millimeter, and Terahertz Waves, 2010

Abstract We demonstrate a continuous THz emission using a low-temperature-grown InGaAs photomixer... more Abstract We demonstrate a continuous THz emission using a low-temperature-grown InGaAs photomixer and a widely tunable dual-wavelength erbium-doped fiber laser as an optical beat source. The wavelength spacing can be tuned from 2.3 nm to 8.8 nm which ...

Intelligent Systems in Design and Manufacturing VI, 2005

ABSTRACT The performance of data and telecommunication equipment must keep up with the increasing... more ABSTRACT The performance of data and telecommunication equipment must keep up with the increasing network speed. Optical interconnection technology is a promising alternative for high throughput systems. The Optical backplane system was demonstrated with waveguide-embedded optical backplane, transmitter board and receiver board. The transmitter and receiver module were prepared for optical PCB, which consists of the metal optical bench, the driver chips, VCSELs, photodiodes and a tapered polymeric waveguide. And parallel optical transmitter and a receiver module were attached onto the processing boards for the interconnection with optical backplane board. The tapered polymeric waveguides are fabricated using the hot embossing technique. And the propagation loss of the waveguide was approximately 0.1dB/cm at 850nm. The waveguide-embedded optical backplane boards were fabricated by using conventional PCB lamination process. The data transmission characteristics of the processing board have been investigated. In our optical backplane system, we demonstrated up to 10Gb/s 27-1 PRBS NRZ data transmission from the transmitter board to the receiver board through optical backplane. The BERs were less than 10-12 under 8Gb/s data rate, which is sufficient level for telecommunications.

Optics express, Jan 26, 2015

In this study, inspired by the frequency-modulated continuous-wave (FMCW) method, an operation sc... more In this study, inspired by the frequency-modulated continuous-wave (FMCW) method, an operation scheme of continuous-wave (CW) terahertz (THz) homodyne system is proposed and evaluated. For this purpose, we utilized the fast and stable wavelength tuning characteristics of a dual-mode laser (DML) as a beating source. Using the frequency-modulated THz waves generated by DML, a cost-effective and robust operation of CW THz system to be applicable to the measurements of thickness or refractive index of a sample is demonstrated. We believe that the proposed scheme shows a potential to the implementations of compact and fast CW THz measurement systems that can be useful in many THz applications.

Transactions of The Korean Society of Mechanical Engineers A, 2003

2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011

We propose a high-speed frequency-scanning optical beat source using a wavelength swept laser and... more We propose a high-speed frequency-scanning optical beat source using a wavelength swept laser and a tunable laser for continuous THz wave generation. The beat frequency is scanned at 1 kHz over a range with a 2.16 THz width.

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013

ABSTRACT The photomixers enables continuous-wave, frequency-tunable terahertz (THz) emitter and d... more ABSTRACT The photomixers enables continuous-wave, frequency-tunable terahertz (THz) emitter and detector by using conventional photonics technology. To increase the emission and detection efficiency, various antennas have been adopted. In this work, we provide experimental characterizations of various kinds of antenna-integrated photomixers by measuring reference THz pulse from an InAs crystal.

2011 International Conference on Infrared, Millimeter, and Terahertz Waves, 2011

... Phys. Lett. 91, 241102-241104 (2007). [3] N. Kim, YA Leem, JH Shin, CW Lee, SP Han, MY Jeon, ... more ... Phys. Lett. 91, 241102-241104 (2007). [3] N. Kim, YA Leem, JH Shin, CW Lee, SP Han, MY Jeon, DH Lee, DS Yee, SK Noh, and KH Park, “Widely tunable dual-mode multisection laser diode for continuous-wave THz generation,” in Proceedings of 35th international conference ...

2011 International Conference on Infrared, Millimeter, and Terahertz Waves, 2011

We demonstrated a fiber-coupled THz time-domain spectroscopy (TDS) system. A THz output power of ... more We demonstrated a fiber-coupled THz time-domain spectroscopy (TDS) system. A THz output power of 132 nW of the THz emitter in the system was measured by a Golay-cell. Water vapor dips in the free space were clearly observed by the THz detector in the system.