http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Externally modulated ns-pulse amplification using an all-fiber system
Sahnggi Park,Chul-Wook Lee,Hyunsung Ko,Ji-Myon Lee,Joon-Tae Ahn,Moon-Ho Park,Su Hwan Oh 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.6
An all ber system of standard single-mode cascaded erbium doped ber ampliers (EDFAs) was used to amplify 3-ns externally modulated pulses, where an ecient removal of background cw power was an inevitable step to avoid gain saturation by the unwanted cw source in high power pulse amplication. It is shown that an appropriate thickness of saturable absorbers can remove, almost completely, the background cw power, as well as the amplied spontaneous emission (ASE). We claim that this experiment demonstrates a most eective way of pulse amplication for all ber systems. We also experimentally and theoretically analyzed the pulse behavior for dierent duty rates as a function of the pump power.
Echelle grating silicon multi/demultiplexers with single-reflection total internal reflectors.
Park, Sahnggi,Kim, Sang-Gi,Park, Jeagyu,Kim, Gyungock Optical Society of America 2012 Optics express Vol.20 No.21
<P>We present a silicon-on-insulator Echelle grating 8-channel demutiplexer showing characteristic features, average insertion loss 2.4 dB measured at 1520~1570 nm, adjacent channel crosstalk 15-18 dB, and channel spacing 11.9 nm. Our Echelle grating is remarked by a total internal reflector (TIR) which reflects incident light by a single reflection in contrast to the double reflections of retro-reflector TIR Echelle gratings.</P>
Temperature, Current, and Voltage Dependences of Junction Failure in PIN Photodiodes
Sahnggi Park,심은덕,박정우,백용순,Jae-Sik Sim,Hyun-Woo Song,Su Hwan Oh 한국전자통신연구원 2006 ETRI Journal Vol.28 No.5
A PIN photodiode having a low dark current of 1.35 nA and a high external quantum efficiency of 95.3% fabricated for a passive optical network receiver. As the current was increased under a high voltage of 38 V and a temperature of 190°C, it was observed that there is a threshold current at 11 mA which induces a junction failure. Experimental data suggest that the junction failure occurs due to the crystal breaking at the end facet as a result of thermal heat or energetic carriers. This threshold behavior of junction failure is a valuable observation for the safe treatment of photodiodes. As long as the current is limited below the threshold currents, we have not observed failure events of our photodiodes.
박상기,Park, Sahnggi 한국전자통신연구원 2020 전자통신동향분석 Vol.35 No.2
Knowledge of the technology, characteristics, and market trends of the latest CPUs used in smartphones, computers, and supercomputers and the research trends of leading US university experts gives an edge to policy-makers, business executives, large investors, etc. To this end, we describe three topics in detail at a level that can help educate the non-majors to the extent possible. Topic 1 comprises the design and manufacture of a CPU and the technology and trends of the smartphone SoC. Topic 2 comprises the technology and trends of the x86 CPU and supercomputer, and Topic 3 involves an optical network chip that has the potential to emerge as a major semiconductor chip. We also describe three techniques and experiments that can be used to implement the optical network chip.
박상기,이명래,Park, Sahnggi,Lee, M.L. 한국전자통신연구원 2016 전자통신동향분석 Vol.31 No.6
스마트팩토리의 세계시장 규모가 2015년 약 177조에서 2020년 약 437조까지 년 평균 20%씩 성장할 것으로 한 보고서는 예측하였다. 한국은 스마트팩토리 보급을 위해 2020년까지 스마트공장을 1만개까지 확산시킨다는 계획이다. 스마트팩토리의 핵심기술은 IoT와 사이버물리시스템(Cyber Physical System: CPS)으로 구성되고 이에 필요한 핵심 하드웨어는 센서소자/모듈, 무선 센서네트워크로 구성된다. 중소기업을 위한 스마트팩토리의 기본적인 구성요소와 통신구조를 논의한다. 그리고 일부 구성요소를 세 기업에 지원한 사례를 알아보고 스마트팩토리를 중소기업에 적용하는 방안 및 문제점을 논의한다.
Su Hwan Oh,Yoon-Jung Park,Sung-Bock Kim,Sahnggi Park,Hee-Kyung Sung,Yong-Soon Baek,Kwang-Ryong Oh IEEE 2007 IEEE photonics technology letters Vol.19 No.17-20
<P>We have demonstrated a very compact eight-channel 200-GHz-spacing multiwavelength laser (MWL) module for the optical line terminal source of wavelength-division-multiplexing passive optical network. The wavelength shift of MWLs and external cavity lasers from the ITU grid was within +0.14 nm for eight channels, which was well matched to the target wavelength shift of less than plusmn0.2 nm. The oscillation characteristics of our MWL module are better than those of conventional MWLs with hybrid integration.</P>
이지면,Chul-Wook Lee,Hyunsung Ko,Ki-Soo Kim,Moon Ho Park,Sahnggi Park,Su Hwan Oh 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.1
The fabrication and the characteristics of a wavelength tunable butt coupled (BT) sampledgrating (SG) distributed bragg reflector (DBR) - planar buried heterostructure (PBH) laser diode (LD) is described. The average threshold current was 25 mA, and the output powers of the fabricated LD were determined to be as high as 12.3 and 24.56 mW at 100 and 200 mA, respectively, with a side mode suppression ratio of about 37 dB. The series resistance and the diode ideality factor of a LD were determined to be 3.7 ± 0.2 and 1.35 ± 0.1, respectively, by exploiting an electrical derivative analysis method. The series resistance of the SGDBR region, however, decreased with increasing current, showing a high resistance (4.4 at < 60 mA), a transient (60 mA 100 mA), and low resistance regions (0.6 at > 100 mA), indicating saturation of the refractive index change.
su-hwan oh,Chul-Wook Lee,Hyunsung Ko,Ji-Myon Lee,Ki Soo Kim,Moon-Ho Park,Sahnggi Park,Suhyun Kim,정영철 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.1I
A butt-coupled (BT) sampled grating distributed Bragg reflector laser diode (SGDBR-LD) was designed and fabricated using a planar buried heterostructure (PBH), enabling a low threshold current and a stable fundamental transverse mode. The maximum output power of the fabricated SGDBR-LD was 24 mW for 200 mA CW operation at 25 C. The measured output power was 14 mW and 13 mW higher than those of a ridged waveguide (RWG) structure and a buried ridge stripe (BRS). Also, the threshold current was 2 times lower than those of the RWG and the BRS. Butt-coupled SGDBR-LD’s with target tuning ranges of 44.4 and 63.4 nm were fabricated, and the tuning ranges were experimentally measured to be 44.4 and 58 nm, respectively. The measured peak periods of the fabricated SGDBR-LD’s were well matched with theoretical values, and the output power was close to the calculated values in both cases. The spectrum of 78 channels spaced by 50 GHz within the tuning range of 35 nm was obtained by using the precise control of the SG and the phase control currents. A side-mode suppression ratio of more than 35 dB was obtained over the whole tuning range. The output power variation was less than 5 dB, which is 4 dB smaller than that of the RWG structure.lEv
Design and Fabrication of High Performance Widely Tunable Sampled Grating DBR Laser
Su Hwan OH,Chul-Wook LEE,Hyunsung KO,Ji-Myon LEE LEE,Ki Soo KIM,Moon-Ho PARK,Sahnggi PARK 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
We have demonstrated a high-performance sampled grating distributed bragg re ector laser by using a planar buried heterostructure for the rst time, where active and passive regions were butt-coupled by using RIE followed by an adequate amount (125 nm thick) of selective wet etching that provided excellent uniformity throughout a quarter of a 2-inch wafer. The measured average coupling eciency was 96 1.7 % per facet. The maximum output power of the fabricated device was 20 mW at 200 mA under CW operation at 25 C. Average threshold current and voltage were approximately 12 mA and 0.8 V. We obtained a total tuning range of 57 nm and a side mode suppression ratio of more than 35 dB in the whole tuning range. Optical output power variation was less than 5 dB, which is 4 dB smaller than that when using a RWG structure.