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2.5 Gbps 광통신용 Distributed Feedback Laser Diode(DFB - LD) 모듈 제작 및 광송신 실험
박경현(K. H. Park),강승구(S. G. Kang),송민규(M. K. Song),이중기(J. K. Lee),조호성(H. S. Cho),장동훈(D. H. Jang),박찬용(C. Y. Park),김정수(J. S. Kim),김홍만(H. M. Kim),박형무(H. M. Park),한정희(J. H. Han),심창섭(C. S. Shim) 한국광학회 1994 한국광학회지 Vol.5 No.3
DFB-LD 칩으로부터 단일모드 광섬유 부착 2.5 Gbps 광통신용 광원인 DFB-LD 모듈을 설계, 제작하였다. DFB-LD 모듈은 광 isolator가 삽입된 2 렌즈 quasi confocal 광학계로 구성된 원통형 서브 모듈과 14 pin butterfly 패키지가 분리된 구성으로서 이들 사이의 전기적 연결은 bias-T 회로가 형성된 하이브리드 기판으로 이루어지도록 설계하였다. 모듈 제작시 정밀한 부품 고정이 요구되는 서브 모듈 조립에는 레이저 웰딩 방법을 사용하였다. 제작된 DFB-LD 모듈은 광결합 효율 20%, -3dB 소신호 변조 대역폭 2.6 ㎓ 이상의 특성을 가졌으며, 온도 순환검사에도 10% 이내의 광출력 변동만을 보임으로써 기계적 신뢰성을 확인할 수 있었다. 제작된 DFB-LD 모듈의 광송신 성능을 실제 2.5 Gbps 광통신 시스템의 광원으로 적용하여 평가한 결과 47 ㎞의 광섬유 전송시 BER 1×10^(-10) 조건에서 최대 -30.2 dBm의 수신감도를 얻었으며, 이 때 전송페널티는 소광비에 의한 것이 1.5 dB, 분산에 의한 것이 1.0 dB로 나타났다. We designed and fabricated the single mode fiber pigtailed DFB-LD module for 2.5 Gbps optical communication system. In the design of the DFB-LD module, we made the module divided into two parts of inner sub-module and outer 14-pin butterfly package and cylindrical shaped sub-module contain quasi confocal 2 lens system including optical isolator and electrical connection between these parts via hybrid substrate of bias T circuit.<br/> Laser welding was used to assemble the sub-module which requires accurate fixing between optical elements. The fabricated DFB-LD module showed optical coupling efficiency of 20% and -3 dB small signal response of more than 2.6 ㎓. We confirmed mechanical reliability of the module by temperature cycle test where the tested module exhibit optical power fluctuation of less than 10%. Finally we evaluated the performance of the fabricated DFB-LD module as light source of 2.5 Gbps optical communication system, sensitivity of -30.2 dBm was obtained through 47 ㎞ optical fiber transmission under the criterion of 1×10^(-10) BER and transmission penalties were 1.5 dB caused by extinction ratio and 1.0 dB caused by chromatic dispersion of normal single mode fiber.
난포 호르몬에 의한 인체 자궁동맥 이완반응과 연령사이의 상관관계에 관한 연구
김연희(Y . H . Kim),박형무(H . M . Park),허민(M . Hur),이무열(M . Y . Lee) 대한산부인과학회 2000 Obstetrics & Gynecology Science Vol.43 No.10
Objective : This study was performed to investigate whether 1) estrogen induces the vasorelaxation mediated by calcium channel in smooth muscle of endothelium-denuded human uterine artery, and 2) the degrees of vasorelaxation have some difference according to age. Methods : The uterine arteries from 18 premenopausal women were obtained at the time of hysterectomy due to various indications and endothelium was denuded. Vascular reactivity was monitored by using Isometric force transducer and recorded by physiograph. Endothelial integrity was assessed by sequential administration of 1 μM norepinephrine(α-adrenergic stimulant) and 10 μM acetylcholine (endotelium -dependent vasorelaxant). Integrity of smooth muscle was measured by administration of 10 μM sodium nitroprusside (endotelium - independent vasorelaxant). A dose-dependent action of estrogen was measured on denuded uterine arteries, pretreated with norepinephrine and potassium chloride. Statistical tests were performed at the 5% level of significance using the SPSS PC+ package. Results : Acethylcholine have little effect but sodium nitroprusside showed marked relaxation, which suggested loss of endothelial function and adequacy of smooth muscle function. The contraction by norephinephrine(1 M) revealed estrogen induced relaxation which was concentration-dependent from 10pg/ml to 10ng/ml in concentration of 17 -estradiol. The contraction by high potassium solution 35mM was also inhibited by estrogen in concentration-dependent manner. The vasorelaxation effect of 17 -estradiol on the contraction evoked by both norepinephrine and potassium revealed reduction according to the increase of age.Conclusion : The results of this study suggested that the decrease of the vasorelaxant effect according to age might be correlated with increase of cardiovascular disease in old age group.
광통신용 1.3 ㎛ Ridge Waveguide Distributed Feedback Laser Diode의 제작과 특성 평가
박경현(K. H. Park),이중기(J. K. Lee),장동훈(D. H. Jang),유지범(J. B. Yoo),강승구(S. K. Kang),김홍만(H. M. Kim),이용탁(Y. T. Lee),박형무(H. M. Park),조호성(H. S. Cho),홍창희(T. Hong) 한국광학회 1994 한국광학회지 Vol.5 No.1
발진파장이 1.3 ㎛인 Ridge Waveguide Distributed Feedback Laser Diode(RWG-DFB-LD)를 제작하고 특성을 평가하였다. 회절격자 형성은 광간섭무늬 노광법을 이용하였고 결정성장은 LPE로 수행하였다. 제작된 RWG-DFB-LD의 발진 임계전류는 67 ㎃이었고, 1296.5 ㎚ 파장에서 측모우드 억제율 30 dB 이상으로 단일 종모우드로 발진하였다. 금지대역폭 측정에 의한 회절격자 결합계수(k)는 40 ㎝-¹로 평가되었다. 소신호 변조특성평가 결과 제작한 RWG-DFB-LD는 1.2 Ith에서 1.99 ㎓의 변조대역폭(f_(-3dB)) 특성을 보였다. We fabricated and characterized RWG-DFB-LDs emitting at 1.3 ㎛ wavelength. For fabrication of the laser diode, inteference fringe of optical beams was used for grating formation and epi layers were grown by LPE. The fablicated RWG-DFB-LD operated in a single longitudinal mode with more than 30 dB SMSR at 1296.5 ㎚ emitting wavelength and its threshold current was 67 ㎃. Coupling coefficient (k) was estimated as 40 ㎝-¹ by means of stop-band measurement. Finally, we show that the RWG-DFB-LD fabricated in this experiment can be applicable as light source of 2.5 Gbps optical communication system from the fact that the small signal response of the RWG-DFB-LD rated up to 1.99 ㎓ at pre-bias level of 1.2Ith.
광통신용 1.55 ㎛ PBH - DFB - LD 스펙트럼 특성
장동훈(D. H. Jang),이중기(J. K. Lee),이승원(S. W. Lee),박경현(K. H. Park),김정수(J. S. Kim),김홍만(H. M. Kim),황인덕(I. D. Hwang),박형무(H. M. Park),조호성(H. S. Cho),홍창희(T. Hong) 한국광학회 1994 한국광학회지 Vol.5 No.1
LPE와 간섭노광법을 이용하여 1.55 ㎛ 파장의 InGaAsP/InP PBH-DFB-LD를 제작하고 스펙트럼 특성을 평가하였다. 제작된 PBH-DFB-LD의 발진 임계전류는 15 ㎃ 이하이며, 1.55 ㎛ 파장에서 광출력 7 ㎽ 이상까지도 단일 종모우드로 동작하였으며 측모우드 억제율 35dB 이상을 얻었다. 본 연구에서 제작된 PBH-DFB-LD 발진파장의 온도 의존 특성은 0.9Å/℃이며, 금지대역폭 측정에 의한 회절격자의 결합계수(k)는 97 ㎝-¹로 평가되었다. PBH-DFB-LD emitting at 1.55 ㎛ wavelength has been fabricated for 2.5 Gbps optical fiber communications. For fabrication of PBH-DFB-LD, inteference expose for grating formation and 3-step LPE epitaxial growth was used. Fabricated PBH-DFB-LD operates in single longitudinal mode with more than 35dB SMSR and its threshold current is less than 15 ㎃. The operating wavelength is 1530~1550 ㎚ with the temperature dependence of 0.9Å/℃. Coupling coefficient(k) was estimated as 97 ㎝-¹ by means of stop-band measurement. PBH-DFB-LD fabricated in this experiment can be applicable as light source for 2.5 Gbps optical fiber communication system.
유지범(J. B. Yoo),박찬용(C. Y. Park),박경현(K. H. Park),강승구(S. K. Kang),송민규(M. K. Song),오대곤(D. K. Oh),박종대(J. D. Park),김흥만(H. M. Kim),황인덕(I. D. Hwang),박형무(H. M. Park),윤태열(T. Y. Yoon),이창희(C. H. Lee),심창섭(C. S. Sh 한국광학회 1994 한국광학회지 Vol.5 No.2
2.5 Gbps 광통신시스템용 수광소자로서 charge plate층을 갖는 링구조의 separate absorption grading multiplication Avalanche photodiode를 제작하고 그 특성을 조사 분석하였다. Avalanche Photodiode의 제작은 Metal-Organic Chemical Vapor Deposition과 Liquid Phase Epitaxy법을 이용한 에피성장과, Br: Methanol을 이용한 채널식각 방법을 사용하였고, passivation과 평탄화는 photosensitive polyimide를 이용하였다. 제작된 APD는 10 ㎁ 이하의 작은 누설전류를 나타내었고, -38~39V의 항복전압을 나타내었다. 제작된 APD를 GaAs FET hybrid 전치증폭기와 결합하여 2.5 Gbps 속도에서 2²³-1의 길이를 갖는 입력 광신호에 대해 10^(-10) Bit Error Rate에서 -31.0 dBm의 수신감도를 얻었다. We fabricated and characterized the InGaAs separate absorption, grading and multiplication (SAGM) Avalanche photodiode (APD) with a chrage plate layer. Channel was employed for the isolation of the active area of APD. Metal-organic chemical vapor deposition (MOCVD) and liquid phase epitaxy (LPE) were used for the epitaxial growth. Channel was formed using wet etching technique. Photosensitive polyimide was used for the passivation and planarization of the device. APD shows very low leakage current smaller than 10 ㎁ and -38~39 V of breakdown voltage. Optical receiver consisting of APD and GaAs FET pre-amplifier shows the sensitivity of -31.0 dBm at 10^(-10) BER (Bit Error Rate) and 2.5 Gbps optical random signal of 2²³-1 in length.
주관종,김동구,윤형진,박형무,Joo, G.C.,Kim, D.G.,Yoon, H.J.,Park, H.M 한국전자통신연구원 1994 전자통신동향분석 Vol.9 No.1
소자가 고속, 고주파화 되고 ASIC 칩의 개발이 가속화되면서 패키징과 interconnection 의 중요성이 더욱 증대되고 있다. 소자의 성능에 가장 직접적인 영향을 주는 것이 1차 패키징인데 현재 가장 많이 실행되고 있는 것이 wire 등에 의한 본딩 방법이었다. 이러한 기존의 방법은 소자의 고속화와 입출력 숫자의 증가에 따라 점차 그 한계를 보이고 있는데 이에 대한 방안으로는 플립칩 본딩 방식에 의한 패키징을 들 수 있다. 약 20여년 전에 IBM 에서 개발된 이래 많은 발전을 거듭한 이 기술은 최근 기본 기술에 대한 특허권의 소멸과 함께 많은 응용 분야에서 개발이 활발히 진행되고 있다. 따라서 본 고에서는 향후의 가장 유력한 패키징 기술로 인정되고 있는 플립칩 본딩 기술의 특징과 제조 관련 사항을 정리함과 동시에 응용 분야, 특히, OEIC(Optoelectronics Integrated Circuit) 분야에서의 이용 및 개발 현황을 분석, 소개함으로써 이 새로운 패키징 기술에 대한 인식을 제고하고자 한다.
수술적 폐경과 자연 폐경에서 호르몬 보충요법 후 골반응의 차이
서유석(Y. S. Suh),박형무(H. M. Park),박선영(S. Y. Park),윤성준(S. J. Yoon),허민(M. Hur) 대한산부인과학회 1999 Obstetrics & Gynecology Science Vol.42 No.10
Objectives: surgical menopause, state of both oophorectomy, shows some different features compared to natural menopause. The purpose of this study was to compare effectiveness of hormone replacement therapy(HRT) in surgical menopause with it in natural menopause. Methods: bone mineral density was assessed in 71 surgically menopausal women at the time of starting HRT and was repeated after one year HRT. 28 were evaluated by quantitative computed tomography (QCT) and 43 were done by dual energy X ray absorptiometry (DXA). We divided the subjects into two groups according to the intervals between oophorectomy and the start of HRT(group 1: within 2 years after surgery, group 2: more than 2 years after surgery). Results: QCT-group 1 included 22 subjects, QCT-group 2 included 6. In group using DXA, 33 subjects were in group 1, and 10 in group 2. In natural menopause, 76 subjects were included and their bone mineral densities were assessed pre- and post-HRT(QCT: group 1, n=13, group 2, n=13, DXA: group 1, n=32, group 2, n=18) 1) Incidences of significantly decreased BMD in spite of HRT in surgically menopaused women were 59.0% in QCT-group 1, 60.6% in spine of DXA-group 1. These incidences are higher than those of natural menopause. 2) After 1 year estrogen replacement in surgical menopause, BMD decreased 6.86% by QCT and 1.15% by DEXA. But, surgical menopause women in group 1, BMD by QCT decreased 7.89%, spine BMD by DXA decreased 2.80%, femur neck BMD decreased 3.08%. Contrary to these results, BMD of natural menopause women increased 4.33%, 2.36%, and decreased 1.83%, respectively. Conclusion: Usual dosages of HRT cannot prevent acute bone loss effectively after both oophoectomized women. So, additional therapy will be prescribed to surgically menopaused women.