• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.8-18
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• 2002

We study complicated nonlinear interactions of two orthogonally polarized pulses with pulse-width of less than 100fsec in the all-optical phase-shift switches, which use soliton pulse-train and fiber-splicing for control pulse to obtain multi-collisional $\pi$-phase-shift and consider Raman response function. We investigate switching performance in various input parameters such as input pulse-width and birefringence of fiber, and find optimum initial conditions for good switching performance in such all-optical switches.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.116-117
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• 2000

전광 네트워크(All-optical Network)에서 중요한 기능을 담당하는 전광 교환기는 전광 교환 소자 (All-optical Switching Element)로 이루어져 있는데, 각 교환 소자들은 스위칭 모듈(SM), 라우팅 제어 처리기(RCP), 헤더 처리 모듈(HPM), 그리고 입/출력 인터페이스 모듈(IIM, OIM)로 이루어져 있다. 스위칭 시스템 내에 도착하는 패킷은 원하는 스위치의 출력단에 도착하기 전에 많은 교환 소자(SE)들을 지나가게 되는데, 이 때 수많은 패킷들이 서로 충돌하게 되며, 이 과정에서 패킷이 손실된다. (중략)

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.492-499
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• 1997

We proposed and studied an all-optical switching device made of a bent nonlinear waveguide and an all-optical logic gate made of a bent nonlinear Y-junction. The proposed devices as switch and a logic function are based on the evolution of nonlinear guided wave along a bent nonlinear waveguide. Since the characteristics of beam propagation depens on the nonlinearity, input power and bent angle of waveguide, the characteristics of output power transmission is calculated by variation the such parameters. Furthermore, by calculating the output power through the nonlinear media with different positions of detector in nonlinear media, we could find the ideal digital switching performance at specific position of detector and implement several all-optical logic functions (AND, OR, XOR) by power contrast between waveguide end and nonlinear media.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.287-291
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• 2009

In this paper, an optical switch/modulator is designed and its light propagating characteristics analyzed using a simplified BPM. The distinctive feature of this switch/modulator is that all its waveguide branches are designed as single-mode. The principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of the fact all waveguides are designed as single-mode, by adjusting the interconnecting waveguide length'of the device the same characteristics as existing up to date devices are obtainable. Numerical results show that the switching characteristics periodically depend upon an interconnecting waveguide length with a spatial of about $150^{{\mu}m}$ in the $Ti:LiNbO_3$ step index waveguide. The design concept would therefore be utilized effectively in fabricating a monolithic high density optical integrated circuit.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.12-13
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• 2002

The performance improvement of 40Gbit/s soliton transmission system employing nonlinear optical loop mirror (NOLM) as all-optical regenerative repeater is investigated. The switching characteristic of NOLM is optimized using our design strategies. By inserting the optical repeater where the eye-penalty of the transmitted signal becomes 1 ㏈, we achieve the improvement of 0.3㏈ eye-penalty resulting in further 480km transmission distance.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.119-122
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• 1989

An intermodal switch based on optically-induced (through optical Kerr effect) periodic coupling in a two-mode waveguide is described and demonstrated. A high power pump beam injected into the two modes of the waveguide produced a periodic modulation of the refractive index profile with a period of modal beat length. this causes an intermodal coupling of the prove beam. The operating principle was successfully demonstrated in an elliptical core two-mode fiber with a counter-propagating pump-probe scheme.

• 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.

• Korean Journal of Optics and Photonics
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• v.7 no.4
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• pp.403-413
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• 1996

We study the propagation of two pulses with orthogonal linear polarizations in a nonlinear periodic dielectric structure with $X^{(3)}$ nonlinearity. Using an envelope- function approach, we derive the coupled nonlinear Schrodinger equations governing the spatio-temporal evolutions of the two orthogonally polarized modes in a nonlinear periodic structure. We then find their solitary-wave solutions referred to as coupled gap solitons. We show that two orthogonally polarized pulses can co-propagate as a coupled gap soliton through a nonlinear periodic structure while each pulse alone will be strongly reflected due to the Bragg reflection. Based on the results, we present an all-optical switching scheme which has a novel architecture and principle. We also study the stability of coupled gap solitons to find the dragging phenomena in a nonlinear birefringent periodic medium.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.8
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• pp.12-20
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• 1998

All-optical networks(AON) are emerging as the next generation broadband networks for wide-area and local-area networks. Many optical switch architectures are currently proposed to realize AON. Specially, optical switches using WDM have a lot of advantages in point of the optical transparency and network topology for B-ISDN services in AON. In this paper, two kinds of Knockout Optical Switching Architectures(KOSA) are proposed for high speed optical ATM networks. We use WDM technologies for them to operate in all-optical area and they are called Architecture-Ⅰ, Architecture-Ⅱ respectively. Each one represents different characteristics according to the number of components and the kind of components, which make KOSA have different performance and system complextity. In order to verify and to compare the performance, these architectures were analyzed and simulated in terms of cell loss ratio, system complexity and buffering speed.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.766-771
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• 2014

Single-ring all-pass filters with various coupling ratios are designed, fabricated, and characterized to assess the validity of the split-step time-domain modeling approach, which is considered for direct simulation of time-domain characteristics, such as optical delay, of various ring resonator devices. When the coupling ratio of the single-ring all-pass filter is 0.4 and 0.8, the delay time is measured to be about 145 and 42 ps respectively, which is comparable to the time-domain modeling results of 151 and 47 ps respectively. The measurements for two- and three-ring all-pass filters are also found to agree quite well with the simulation results. With these results it is confirmed that the split-step time-domain model could be efficiently incorporated into an optical-communication simulation module for ring resonator delay components in an all-optical packet switching system.