• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.323-330
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• 2005

We fabricate PIN PD (Positive Intrinsic Negative Photo-Diode) for CWDM optical repeater and optical transmission system, and analyze theoretically the characteristics to verify the capability of device fabricated. Furthermore, we integrate CWDM filter into PD package to enhance the cost and the performance when compared to the conventional system, in which CWDM filter and PD package are linked by optical fusion splicing. The integrated CWDM PD is fabricated by three steps as follows: CWDM filter design, PD packaging, and product assembly and test. The results of measurement for PD fabricated reveal 0.5 dB bandwidth of 17 nm, isolation over 60 dB at transmission port and over 20 dB at reflection port. Also, the IMD3 for wireless communication is over 63 dBc, and the responsivity of PD presents over 0.9 A/W for 20 samples of the total 23 PD. The total insertion loss reduces about 0.4${\~}$0.7 dB due to the integrated assembly of CWDM and PD.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.87-92
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• 2008

This study presents the design methods that will enable high speed communication companies to establish high efficiency optical communication network at a low cost. This study compares and analyzes CWDM and DWDM technology that transmit multiple optical signals through an optic core, and describes compensation of deteriorated optical signal, which occurs in long distance data transmission, through the stabilization of TX/RX terminal to enable long distance data transmission. CWDM based line access multiplexer increases concentration efficiency by eight times by providing 4:1 concentration subscriber network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1263-1269
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• 2012

This paper is the research on the heated CWDM optical transmitter for the wavelength compensation at the low temperature. In general, the wavelength deviation of DFB laser is around 0.1 nm/C. The wavelength of DFB laser shifts to longer(shorter) wavelength according to the temperature increase(decrease). Typical CWDM optical communication network has 20 nm channel spacing from reference center wavelength per each channel. There is some limitation problem in the range of operating temperature due to the channel interference. For solving the limited temperature range problem, especially at the low temperature, we use the heater on the DFB laser. As a result, we could realize the CWDM optical transmitter to meet +/-6.5 nm from reference center wavelength in the range of temperature at $-40{\sim}+85^{\circ}C$, which is applicable to the industrial field.

• Journal of Audiology & Otology
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• v.25 no.2
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• pp.104-109
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• 2021

Background and Objectives: To assess whether the audiological and clinical outcomes of type 0 tympanoplasty (T0) performed using cartilage were comparable with those of ossiculoplasty in patients who underwent canal wall down mastoidectomy (CWDM). Subjects and Methods: This study included patients who had chronic otitis media with cholesteatoma and underwent CWDM with ossiculoplasty involving partial ossicular replacement prosthesis (PORP), total ossicular replacement prosthesis (TORP), or T0. Anatomical success rates and hearing outcomes were analyzed. Results: Seventy-two patients were included in this study; 29 of them underwent CWDM with T0, 27 underwent CWDM with PORP, while 16 underwent CWDM with TORP. The difference in mean improvement in the air-bone gap (ABG) between the groups was not significant. The differences in the rates of ABG closure to ≤10 dB HL (p=0.030) and ≤20 dB HL (p=0.029) were significant. There were significant differences in improvements in the ABG at 3 kHz among the PORP, TORP, and T0 groups. Conclusions: The audiological outcomes of CWDM with ossiculoplasty seemed to be better than those of CWDM with T0 with no significant difference in the incidence of complications following ossiculoplasty and T0.

• Korean Journal of Audiology
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• v.25 no.2
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• pp.104-109
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• 2021

Background and Objectives: To assess whether the audiological and clinical outcomes of type 0 tympanoplasty (T0) performed using cartilage were comparable with those of ossiculoplasty in patients who underwent canal wall down mastoidectomy (CWDM). Subjects and Methods: This study included patients who had chronic otitis media with cholesteatoma and underwent CWDM with ossiculoplasty involving partial ossicular replacement prosthesis (PORP), total ossicular replacement prosthesis (TORP), or T0. Anatomical success rates and hearing outcomes were analyzed. Results: Seventy-two patients were included in this study; 29 of them underwent CWDM with T0, 27 underwent CWDM with PORP, while 16 underwent CWDM with TORP. The difference in mean improvement in the air-bone gap (ABG) between the groups was not significant. The differences in the rates of ABG closure to ≤10 dB HL (p=0.030) and ≤20 dB HL (p=0.029) were significant. There were significant differences in improvements in the ABG at 3 kHz among the PORP, TORP, and T0 groups. Conclusions: The audiological outcomes of CWDM with ossiculoplasty seemed to be better than those of CWDM with T0 with no significant difference in the incidence of complications following ossiculoplasty and T0.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.180-183
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• 2005

광주파수에서 대역을 나누어주는 광필터를 이용하여, 기존의 2 코어를 이용한 단방향 광통신을 1 코어를 이용한 양방향 통신으로 전환하여 광선로 절감효과를 얻을 수 있다. 그러나 그런 양방향 통신에서 CWDM (coarse wavelength-division multiplexing) 광채널들에 대한 채널 감시가 요구된다. 정확한 정보전달을 위하여 광원의 특성을 모니터하고, 또한 보드의 신호 레벨에서 감시를 통하여 신호의 오전달을 감시한다. 본 발표논문에서는 광선로 절감에 따른 CWDM 광채널의 성능 개선을 위한 감시기술에 대하여 설명하고, 망교체시에 다른 선로에 영향을 최소로 하는 적절한 감시기술을 설명한다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.232-233
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• 2003

MZI 하나를 이용하여 한 단을 구성한 CWDM 설계에서는 출력 특성이 sine wave 의 제곱 특성을 가지므로 각 채널당 통과 대역이 좁다. 이러한 특성은 WDM System 에서 Laser Source 의 온도 변화에 의한 파장 변화에 대해 좋은 특성을 보이지 못함을 의미한다. 따라서 Laser Source 의 파장 변화에 좋은 특성을 갖는 넓은 통과대역을 갖을 필요가 있다. 본 연구 그룹은 MZI 2개와 3개를 이용하여 평평한 출력 특성을 갖는 4 채널 CWDM 광 도파로 소자의 설계와 해석을 발표한바 있다. (중략)

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.226-229
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• 2003

본 논문은 Uncooled DFB-LD를 광원으로 사용하는 일반적인 8채널 구조의 CWDM시스템에 대해 메트로 파장대를 사용하여 최대 15채널까지 증설이 가능한 시스템 구조에 대한 제안 및 특성을 시뮬레이션 하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.6
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• pp.412-419
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• 2001

In accordance with the PON(passive optical network) could be setup, effective connections with light sources, optical detectors, and optical fibers are the best sensitive points to represent the efficiency of network. Therefore, in this paper we designed and fabricated optical transceiver connection chip that was consisted of channel waveguide, Y-branch, and CWDM on the 2" BK7 glass substrate. This chip can be used for 1.31/1.55${\mu}{\textrm}{m}$ CWDM network and 1.55${\mu}{\textrm}{m}$ region dense WDM network.work.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.221-222
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• 2006