• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.995-997
• /
• 1998

The experimental optical cross-connect based on delivery and coupling switch features all-optical property. It consists of erbium-doped fiber amplifiers, arrayedwaveguide gratings, optical switches and optical combiners. In 4 channel wavelength division multiplexing with 1.6 nm spacing, the difference in power level among channels for output signals from the optical cross-connect was within 2 dB.

• Korean Journal of Optics and Photonics
• /
• v.11 no.3
• /
• pp.163-165
• /
• 2000

We propose a new structure of optical cross connect based on a WDM MUX/DEMUX pair and switchable mirrors. In experiment, we demonstrate the operation of the optical cross connect using an optical fiber loop mirror connected to a $2\times2$ optical switch as a switchable mirror.mirror.

• Journal of Electrical Engineering and information Science
• /
• v.3 no.3
• /
• pp.336-341
• /
• 1998

We describe the architecture of an optical cross-connect (OXC) which is modular in structure and is able to be upgraded to a virtual wavelength path by adding wavelength converters. The additional feature of the OXC is the all-optical nature. It can be implemented with commercial components including mechanical optical switches. As a result of the test on the experimental OXC, it has been shown that 2.5 Gb/s signal can be transmitted via the OXC through 100 km length o an ordinary single mode fiber with 3 dB penalty.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.8
• /
• pp.543-548
• /
• 2003

In this paper, we have proposed and fabricated a two-axis rotational micro-mirror with large tilt angle. Such a micro-mirror is a key element for N$\times$N high capacity optical cross-connect switches. The micro-mirror is required to have large tilt angle to increase the capacity of the cross-connect switches. For larger micro-mirror tilt angle between the grounded mirror plate and the bottom electrode is to be large enough to provide space for the tilting of the mirror. For our proposed structure, the gap was produced in such a way that the grounded mirror plate and the bottom electrode were made separately in different substrates by using the bulk micromachining technology, and combined later by employing self-align technique. As a result, a large tilt angle has been achieved without using additional actuators. The measured tilt angles were as large as $\pm$5.5$^{\circ}$ and $\pm$8.4$^{\circ}$ in the x and y direction respectively, and the pull-in voltages for the two directions were 380 V and 275 V respectively. Finally the fabricated mirror was successfully utilized to steer the optical beam. To our knowledge, our micro-mirror has the best performance among the micro-mirrors reported internationally so far.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.11
• /
• pp.15-21
• /
• 1999

The scalability of optical cross-connect nodes is analyzed based on the limiting factor of transmission performance. The limiting factors considered are ASE noise accumulation and gain saturation in the optical amplifiers, and crosstalk in both wavelength multiplexers/demultiplexers and optical switches. When the wavelength multiplexer/demultiplexers crosstalk is lower than 25dB, Power Penalty is below 1dB for the cascaded transmission of 10 nodes with 4 input/output ports. When 10Gbps signals are transmitted through nodes with 4 and 16 input/output Ports, performance degradation due to switch crosstalk is dominant compared to that due to ASE noise accumulation if the switch crosstalk is larger than 30dB and 45dB, respectively. For the single stage transmission of 10Gbps signal with 21dB fiber link loss, the maximum loss of optical cross-connect nodes must be under 34dB to achieve the BER of $10^{-12}$.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.3
• /
• pp.251-258
• /
• 2003

Optical Switching Matrix (OSM) or Optical Multistage Interconnection Networks (OMINs) comprising photonic switches have been studied extensively as important interconnecting blocks for Optical Cross Connects (OXC) based on Optical Burst Switching (OBS). A basic element of photonic switching networks is a 2$\times$2 directional coupler with two inputs and two outputs. This paper is concerned with the diagnosis of multiple crosstalk-faults in OSM. As the network size becomes larger in these days, the conventional diagnosis methods based on tests and simulation become inefficient, or even more impractical. We propose a simple and easily implementable algorithm for detection and isolation of the multiple crosstalk-faults in OSM. Specifically. we develop an algorithm for isolation of the source fault in switching elements whenever the multiple crosstalk-faults arc detected in OSM. The proposed algorithm is illustrated by an example of 16$\times$16 OSM.

• Proceedings of the KIEE Conference
• /
• 2001.11c
• /
• pp.359-361
• /
• 2001

This paper reports on the development of Micro optical cross connector(MOXC) performance evaluation system using DAQ board and Labview. The system is composed of optical part, driving circuit and software part, this evaluation system can measure insertion loss, response time and life time of MOXC, this system canbe used in mass production of MOXC.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.1B
• /
• pp.1-7
• /
• 2004

Increase of internet users and new type of applied traffic such as game, news, distributed computing, online image conference, and real time audio and video have leaded to demand for more bandwidth for each application. This algorithm represents a complex optical exchanger having typical wavelength switching function and time-slotted transmission function. Performance assessment of the proposed OXC (Optical Cross connect) sttucture defines LFS (Limit Frame Size) and VFS (Variable Frame Size) for classification by packet type and calculates the channel effect and loss probability depending the demanded bandwidth by access node increase. Optical exchanger in this type of structure can guarantee future network expansion as well as decrease of frame collision resulted from node increase.

• The Optical Journal
• /
• s.97
• /
• pp.67-72
• /
• 2005

광통신 기술의 발전으로 광 스위치 분야의 개발이 활발히 진행되고 있으며 이중에서도 MEMS를 이용한 광 스위치가 주류를 이루어 개발되고 있다. 특히 최근에는 OXC(Optical Cross Connect)에 사용되는 MEMS actuator로 구동되는 미소거울이 스위치내부에 사용되는 유일한 대안으로 떠오르면서 많은 기업들이 특허를 출원하고 있다. 현재 미국이 압도적인 기술우위를 보이고 뒤이어 일본이 현재 많은 개발을 서두르고 있음을 볼 수 있다. 한국은 미래의 주역이 될 것으로 보이는 MEMS 기술개발에 많은 투자를 해야 할 것이며 더불어 이를 이용한 응용 분야에 대한 상호 복합적 연구 또한 진행해야 세계 기술시장에 당당히 설 수 있을 것으로 보인다.

• Proceedings of the Optical Society of Korea Conference
• /
• 1995.06a
• /
• pp.210-215
• /
• 1995

Technology development toward the use of LiNbO3-based acoustic tunable filters as WDM 2$\times$2 cross-connect switches is reviewed. Recenly, it was found that a fundamental behavior of multi-wavelength Bragg scattering critically affects the crosstalk performance of the acousto-optic tunable filter. We revuew serveral reported methods of overcoming the performance degradation. We will eventually ask whether the device is up to task of WDM optical switching.