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다결정을 이용한 실온에서의 분광 홀버닝 광메모리 구현에 관한 연구
조재헌,백운식,장기완 경희대학교 레이저공학연구소 2001 레이저공학 Vol.12 No.-
The extremely high data densities can be obtained by spectral holeburning, so persistent holeburning has been studied on crystal that doped sm2+ ions at room temperature. To improve performance of persistent spectral holeburning system, we replace a dye laser system by our Littman type external cavity tunable laser diode system.
Littman형 파장가변 다이오드 레이저 시스템의 설계.제작 및 성능평가
조재헌,박준구,백운식 한국광학회 2001 한국광학회지 Vol.12 No.4
상용 반도체 레이저 다이오드에 Littman형 외부공진기를 결합하여 파장기변 레이저 다이오드 시스템을 제작하였다. 0차 출력광은 단일종모드로 동작하여 CFP의 분해능인 9MHz이내의 선폭을 예상할 수 있었으며 다이오드 구동전류 140mA 및 동작온도 $25^{\circ}C$의 조건하에서 거울을 수동나사로 회전시키는 성긴 튜닝(coarse tuning)시 3.475nm 의 파장가변 범위를 보였으며 PZT(piezoelectric transducer)에 200Hz의 톱니파 전압을 인가해서 거울을 회전시키는 미세튜닝(fine tuning)시 0.042nm의 범위내에서 연속적인 파장가변이 가능하였다. A Littman type tunable external-cavity diode laser system was developed. The laser output which is the Oth-order diffracted beam from a diffraction grating in an external cavity is a single longitudinal mode. Its FWHM was measured as less than 9 MHz. With the diode driving current of 140 mA and operating temperature of $25^{\circ}C$, the coarse tuning range of 3.475 urn was measured. A fine tuning experiment in which an external mirror was rotated by a PZT driven by a sawtooth wave was performed, and its tuning range of 0.042 urn was measured. sured.
구동 증폭단의 선형화 회로를 이용하여 출력전력을 개선시킨 W-band CMOS 전력 증폭기
조재헌(Jaeheon Cho),박창근(Changkun Park) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.11
A 77 GHz CMOS Power Amplifier(PA) with diode linearizer is introduced at the drive stage. Transformer, which improved Q-factor for high gain transmission, was applied to power stage. PA was designed using a 65 nm RF CMOS process. As a result of the simulation, the gain is 16.8 dB or more and the change in the gain per GHz within the target frequency band is 0.267 dB or less. P1dB is a minimum of 13.5 dBm, Psat is a minimum of 15.19 dBm, and peak PAE is a minimum of 10.3%. The core size is 0.028 mm².
구동 증폭단의 선형화 회로를 이용하여 출력전력을 개선시킨 W-band CMOS 전력 증폭기
조재헌(Jaeheon Cho),박창근(Changkun Park) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.11
A 77 GHz CMOS Power Amplifier(PA) with diode linearizer is introduced at the drive stage. Transformer, which improved Q-factor for high gain transmission, was applied to power stage. PA was designed using a 65 nm RF CMOS process. As a result of the simulation, the gain is 16.8 dB or more and the change in the gain per GHz within the target frequency band is 0.267 dB or less. P1dB is a minimum of 13.5 dBm, Psat is a minimum of 15.19 dBm, and peak PAE is a minimum of 10.3%. The core size is 0.028 mm².
차량용 열교환기의 주름진 루버 휜에 대한 3차원 성능해석
박봉수,조재헌,한창섭 대한설비공학회 2002 설비공학 논문집 Vol.14 No.2
A three dimensional numerical analysis of the corrugated louver fin for a vehicle heat exchanger was performed. The heat transfer rate and the air pressure drop of the corrugated louver fins for a slim heater were compared with experimental results at the same operating conditions. As for the slim heater fin, we found an optimum fin pitch at certain operating conditions. As the fin pitch increased, the air pressure drop decreased. The vertical or flat top fin was superior to the common declined fin in the aspect of heat transfer performance. As the louver length increased, both the heat transfer rate and the air pressure drop increased.