• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.166-167
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• 2003

실리콘 기판 위에 제작되는 실리카 물질은 낮은 가격, 파이버와의 높은 결합 효율 그리고 고집적화의 장점으로 PLC(Planar Light Circuit)에 사용되고 있다. PLC 광소자 중에서 열 광학 스위치(Thermo-optic switch)는, NⅹN 매트릭스 스위치와 Add／drop multiplexer 등 비교적 낮은 속도를 갖는 광 신호 처리를 위해 중요한 소자이다. 기존의 열 광학 스위치의 경우, 방향성 결합기를 사용한 Mach-Zehnder 구조로써, 위상 제어단에서 두 도파로 간의 광 전력 교환을 막기 위해 방향성 결합기의 양쪽 끝단에에 굽은 도파로를 이용한다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.188-189
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• 2001

광통신 분야에서 파장분할 방식(WDM)이 널리 이용됨에 따라, 파장 가감기는 광통신의 핵심 소자로 주목받고 있다. 특히, 광섬유 브래그 격자를 이용한 전광섬유(All-fiber) 소자는 좁은 선택파장 특성을 만족시키며 삽입손실이 작다는 장점을 가지고 있다. 본 논문에서는 기울어진 광섬유 브래그 격자(Tilted FBG)와 모드분할 방향성 결합기(Mode Selective Coupler, MSC)의 광섬유 공간모드(spatial mode)결합을 이용한 전광섬유 파장 가감기에 대하여 설명하고 있으며, 보다 좋은 성능의 소자제작을 위해 몇 가지 새로운 제작방법을 제안하고 구현하였다. (중략)

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.9-14
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• 2004

Lightwave communication system for Wavelength division multiplexing(WDM) consists of multiplexer, demultiplexer and optical Inter. But, the existing multiplexer, demultiplexer and optical filter is difficult to minimize system and reduce weight because they are not integrated device type. In this paper, thus, we propose the OADM baed on a Mach-Zehnder interferometer(MZI) with FBG(fiber Bragg Slating) in the interferometer Ems. The OADM using FBG. and MZI is able to minimize system and reduce weight. We analyze output characteristics of OADM and present the optimum design data through the computer simulation and experimentation. Also unposed OADM fits for DWDM(Dense WDM) system because of wide bandwidth by tuning narrow linewidth.

• Journal of the Optical Society of Korea
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• v.6 no.2
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• pp.27-32
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• 2002

An integrated optical 2$\times$2 add/drop multiplexer in X-cut, Y-propagating LiNbO$_3$ has been demonstrated. The device consists of passive polarization splitters and acousto-optical mode converters with weighted coupling utilizing tapered acoustical directional couplers; their specific design and properties are discussed. The insertion loss has been measured to be about -8.16 ㏈ and -8.6 ㏈ for TE and TM polarizations, respectively. The device shows a 3 ㏈ bandwidth of 2.3 nm, a tuning rate 8.34 nm/MHz around λ = 1554 nm, and a sidelobe suppression of about 14.5 ㏈. Optimum operation is achieved with a RF drive power of about 43 ㎽. Multi-wavelength operation has been demonstrated.

• 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.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.78-79
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• 2000

재구성이 가능한 광 크로스-커넥트(optical cross connect)는 전광 네트워크를 구성하기 위한 핵심소자 중의 하나이다. 일반적인 구조의 파장분배기는 공간분할 스위치(space division switch)를 두 쌍의 파장 다중화기(multiplexer)와 역다중화기(demultiplexer)의 가운데에 삽입하여 구현된다$^{(1)}$ . 최근에, 광섬유 브래그 격자와 광스위치 쌍을 직렬 연결하여 재구성이 가능한 광 크로스-커넥트가 제안되었다$^{(2)}$ . 그러나, 이 구조는 광신호에 따라 광섬유 브래그 격자에 반사되면서 겪는 광스위치에 의한 삽입손실이 다르다는 문제점이 있다. 이러한 문제를 해결하기 위하여 본 논문에서는 한 쌍의 파장 다중화기/역다중화기와 파장가변 광섬유 브래그 격자를 이용한 새로운 구조의 광 크로스-커넥트를 제안하고자 한다. 또한, 제안된 구조는 일반적인 구조의 파장분배기에 비해 파장 다중화기/역다중화기의 개수를 반으로 줄일 수 있는 장점이 있다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.334-335
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• 2003

현재 기지국과 중계기 사이의 광선로에 사용되고 있는 1310 nm와 1550 nm 파장이외에 OADM (optical add-drop multiplexer)을 사용하여 새로운 2개 파장을 광선로에 추가로 연결함으로써 광선로 임차사용의 효율을 증대시키는 4파장 광중계기의 구현시 drop신호는 삽입손실 ­3 dB 이하의 저손실특성이 요구되며 isolation 신호는 통상 ­40 dB 이상의 고품질이 요구된다. 그러나 이와같은 성능의 광모듈을 실제로 구현하기 어렵다. 따라서 많은 광결합 부품의 조합을 통해서도 drop또는 isolation 특성은 4파장 광중계기를 실용화하기 어려울 만큼 저하된다. (중략)

• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.340-344
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• 1997

We proposed and demonstrated a tunable wavelength optical add/drop multiplexer(OADM) employing piezoactuated fiber grating pairs and polarization beam splitters. We used piezostack act as a fiber stretcher, using the fact that the resonant wavelength of the grating can be controlled by the axial strain along the fiber grating. The polarization controlled configuration showed high stability because the reflected signals from the two identical gratings are dropped or added not by interference but by polarizations of the beams. We could add and drop not noly 1549.3nm signal channel(original gratings), but also 1550.1nm(tuned gratings) with PZT actuators and in both cases, we found that the rejection of adjacent channels was more than -26dB, and signal leakage at the gratings was less than -34dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.220-223
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• 2006

In this paper, we studied about the level controller of optical signal with 40 channels by 4 VOA(Variable Optical Attenuator) with 12 channels. Total 8 microprocessors control 40 chamois for control of optical signal level so that a microprocessor controls 5 channels each. Moreover a microprocessor was added to communicate with outside and transfer instruction to each microprocessor. The output optical signal is measured and VOA is controlled as a result of it. The VOA outputs is inputted into PD(Photo Detector) at once. We could control multi-channel optical signals simply like this.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.644-647
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• 2004

Optical add/drop multiplexers (OADMs), one of the new network elements, will play a key role enabling greater connectivity and flexibility in the dense wavelength-division multiplexing (DWDM) networks. The importance of OADMs is that they allow the optical network to be local transmitting/extraction on a wavelength-by-wavelength basis to optimize traffic, efficient network utilization, network growth, and to enhance network flexibility. Also, the automatic assembly system of micro optical filters and fibers is a key technology in the development of optical modules with high functionality. Recently, one of remarkable tends in the development of optical communication industry is the miniaturization and integration of products. In this research, we have developed a system capable of automatic alignment of a film filter and a lensed fiber in order to improve the speed and losses in the optical fiber to filter alignment of optical modules. Using the developed automatic alignment system and silicon optical benches, we have fabricated the micro OADM and measured the insertion loss and aging effect.