• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.52-59
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• 1997

In this paper, we propose a system design for a parallel3-dimensional optical interconnection network utilizing variable grating mode liquid crystal devices (VGM LCD's) which are optical transducers capable of performing intensity-to-spatial-frequency conversion. The proposed system performs real-time, reconfigurable, but blocking and nonbroadcasting 3-dimensional optical interconnections. The operating principles of the 3-D optical interconnection network are described, and some of the fundamental limitations are addressed. The system presented in this paper can be directly used as a configuration of switching elements for the 2-D optical perfect-shuffle dynamic interconnection network, as well as for a B-ISDN photonic switching system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.862-869
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• 2000

In a switch routing system, buffers are indispensible to prevent signal collision during routing process. For a photonic switching system, optical buffers are also indispensible if the system requires an active routing rather than a simple optical cross-connect(OXC). To cope with WDM technologies in optical comminication systems in these days, photonic switching system also has to deal with WDM signals. Therefore, optical buffers needed in a switching system has to be routed to the same output. For the receiver to recognize these signals separately, parallel WDM signals during rearrangement process. In this paper, we propose a novel all optical WDM output buffer whose structure, hardware, SNR and BER characteristics are improved a lot comparing with those of previously reported ones. From the analysis of the proposed buffer, the new buffer can hold 255 WDM cells keeping BER of 10-9 as long as a contrast ratio(gain on-off ratio) of optical gate(semiconductor optical amplifier) nside the buffer is 30dB.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.253-260
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• 1996

In this paper, a simple scheme of two-stage free-space photonic swiching system for nonblocking optical interconnections has been investigated using holgorams. The multistage system requires a smaller number of interconnections for a given number of inpuut-output nonblocking ports than the single stage system does. Here hologram elements were used to change interconnection beam paths. In order to increase the idffraction efficiency of the hologram elements in photographic plates, a bleaching technique was used, which converts the amplitude hologram to the phase hologram. To show sthe feasibility of our optical interconnection system, it was implemented using the bleached hologram arrays and an LCTV spatial light modulator, and the sytem as a photonic switching system was demonstrated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.53-58
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• 2004

In this paper, the low-phase dual-band VCO, by adding switching circuit with PIN diode at feedback loop of the oscillation part having negative-resistance, is realized. In order to reduce the phase noise of the VCO, PBG structure applied to the ground plane of the resonator. When applying for PBG structure, output power is -9.17㏈m and phase noise is -102㏈c/Hz at 5.25㎓, output power is -5.17㏈m and phase noise is -101㏈c/Hz at 1.8㎓, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.174-174
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• 2014

Memristor devices are one of the most promising candidate approaches to next-generation memory technologies. Memristive switching phenomena usually rely on repeated electrical resistive switching between non-volatile resistance states in an active material under the application of an electrical stimulus, such as a voltage or current. Recent reports have explored the use of variety of external operating parameters, such as the modulation of an applied magnetic field, temperature, or illumination conditions to activate changes in the memristive switching behaviors. Among these possible choices of signal controlling factors of memristor, photon is particularly attractive because photonic signals are not only easier to reach directly over long distances than electrical signal, but they also efficiently manage the interactions between logic devices without any signal interference. Furthermore, due to the inherent wave characteristics of photons, the facile manipulation of the light ray enables incident light angle controlled memristive switching. So that, in the tautological sense, device orienting position with regard to a photon source determines the occurrence of memristive switching as well. To demonstrate this position controlled memory device functionality, we have fabricated a metal-semiconductor-metal memristive switching nanodevice using ZnO nanorods. Superhydrophobicity employed in this memristor gives rise to illumination direction selectivity as an extra controlling parameter which is important feature in emerging. When light irradiates from a point source in water to the surface treated device, refraction of light ray takes place at the water/air interface because of the optical density differences in two media (water/air). When incident light travels through a higher refractive index medium (water; n=1.33) to lower one (air; n=1), a total reflection occurs for incidence angles over the critical value. Thus, when we watch the submerged NW arrays at the view angles over the critical angle, a mirror-like surface is observed due to the presence of air pocket layer. From this processes, the reversible switching characteristics were verified by modulating the light incident angle between the resistor and memristor.

• Proceedings of the Optical Society of Korea Conference
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• 1995.06a
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• pp.43-52
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• 1995

For massicely parallel optical interconnections, we propose three types of planar optical configurations for crossover photonic switching netweek, backboard optical signal distribution, and high speed packet address detection. The planar overalsy allow 2-D pixel arrays located on a wafer scale intergated circuit to be interconnected in a compact and vibrationally robust configuration. By the laser writing technique surface relief of microopical Fresnel lenses and multiplex gratigs used in the planar optics are successfully fabricated.

• Electronics and Telecommunications Trends
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• v.31 no.6
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• pp.57-66
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• 2016

통신망은 향후 통신 및 셀기반 통신망에 필요한 고속, 데이터 속도 및 투명성(transparency) 그리고 유연성(flexibility)을 제공하기 위해 빠르게 진화하고 있다. 전광 패킷 스위칭 망(all optical packet switching) 구조는 향후 급속도로 증가하는 데이터 통신 트래픽을 원활히 수용하기 위해서 싱글 홉 및 멀티 홉 전광 패킷 스위치 망의 요구사항을 만족하는 스위칭 속도, 성능, 확장성, 경제성 등을 고려한 실제 구현 가능한 구조의 필요성이 최근 대두되고 있다. 본 논문에서는 기존의 광 패킷 스위칭 기술의 한계를 극복할 수 있는 전광 멀티 홉 네트워크 기술을 기반으로 포토닉 패킷 스위칭 망을 구현하고자 세계적으로 연구되고 있는 전광 멀티 홉 네트워크 구조, 포토닉 패킷 스위칭 구조 그리고 시간동기 방법에 대해 최근의 연구동향을 분석한다.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.100-104
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• 2007

We have measured the optical spectra while varying the temperature of photonic crystal fibers (PCFs) with periodic air holes in the cladding. These are liquid crystal infiltrated fibers. For the liquid crystal infiltrated PCFs, we obtained the transmission of several wavelengths at specific temperatures. The transmission power could be reduced by about $10\sim15dB$ by varying the applied temperature in the liquid crystal PCF. We expect that it is applicable as a wavelength switching device in the specific wavelength band.

• ETRI Journal
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• v.31 no.6
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• pp.770-777
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• 2009

We have developed a fully functional reconfigurable optical add-drop multiplexer (ROADM) switch module using a polymer integrated photonic lightwave circuit technology. The polymer variable optical attenuator (VOA) array and digital optical switch array are integrated into one polymer PLC chip and packaged to form a 10-channel VOA integrated optical switch module. Four of these optical switch modules are used in the ROADM switch module to execute 40-channel switching and power equalization. As a wavelength division multiplexer (WDM) filter device, two C-band 40-channel athermal arrayed waveguide grating WDMs are used in the ROADM module. Optical power monitoring of each channel is carried out using a 5% tap PD. A controller and firmware having the functions of a 40-channel switch and VOA control, optical power monitoring, as well as TEC temperature control, and data communication interfaces are also developed in this study.

• Electronics and Telecommunications Trends
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• v.15 no.2 s.62
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• pp.15-31
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• 2000

IP 패킷스위칭을 수행할 수 있는 WDM 기반의 대용량 광패킷스위칭 시스템을 위해 입력광 신호 속도 10Gb/s의 16 x 단위 스위치로 구성되는 출력 버퍼링 방식의 방송 및 선택형스위치 구조가 제안되었다. 기존의 광소자는 광특성 때문에 집적광 집적화 논리회로(PCL)의 제작이 쉽지 않았으나 최근 세계적으로 어레이형 집적화 광소자의 개발 추세가 급속도로 진전되고 있어 대용량의 광교환기 시스템 구조는 기존의 교환기 시스템과 유사한 형태 및 구조가 가능하다.