• Proceedings of the KIEE Conference
• /
• 2006.07d
• /
• pp.2013-2014
• /
• 2006

For large capacity optical CDMA networks, we propose a shared-type encoder/decoder based on an tunable wavelength conveter (TWC) and an arrayed waveguide grating (AWG) router. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using three types of wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC), the generalized multi-wavelength Reed-Solomon code(GMWRSC) and the matrix code. Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.656-658
• /
• 1997

AWG designed in this paper is considered with flat passband characteristics in the channel as a method for solving frequency stability problems of the sources in the conventional optical filters. This device can acquire the flat passband characteristics by inserting the multimode wave guides utilizing the self imaging effec between input wave guides and first star coupler. BPM simulation results show that the excess loss is smaller than 6.5 dB, the crosstalk is less than -22 dB and the 1 dB passband is about 50 GHz in the central channel.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.7
• /
• pp.6-13
• /
• 1998

To constoruct a multi-channel system like Optical Frequency Division Multiplexing (OFDM) with the vast amount of transmission capability, a frequency stabilization is essential technique for getting narrower channel spacing and for minimizing fluctuation of oscillation frquency of each channel. This paper proposes a novel multi-channel optical frequency stabilization scheme that uses wavelength crossover properties of a Arrayed Waveguide Grating(AWG). The proposed scheme includes an effective control algorithm that carries out frequency stabilization of all channels through a simple control circuit, simulaneously. And also, a design method of AWG is included which has higher resolutio in consideration of system loss.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.12
• /
• pp.2828-2833
• /
• 1997

In this paepr, we have proposed an enhanced TDM with WDM hybrid photonic switching architecture, which has much simpler configuration and requires less hard ware. the basic module consists of arrayed waveguide grating (AWG) for wavelength division, compressor and fiber delay lines for time division. When compared with other systems, we proved that the proposed switch is suitable for large capacity photonic switching system due to less complexity and lower cost in implementation than the previous ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.655-657
• /
• 2004

채널 레벨 컨트롤러는 DWDM(Dense Wavelength Division Multiplexing) 방식의 OXC(Optical Cross Connect), OADM(Optical Add/Drop Multiplexer), 광 증폭기(EDFA : Erbium Doped Fiber Amplifier) 둥의 시스템에서 채널별 광신호의 세기를 조절하여 시스템의 신뢰성을 높이는 중요한 제어기다. 본 논문에서는 12채널 VOA(Variable Optical Attenuator) 4개를 사용하여 40채널의 광 신호 레벨을 제어할 수 있는 컨트롤러를 구현하였다. 각 채널의 광 신호 레벨을 제어하는데 하나의 마이크로 프로세서가 5개의 채널을 제어하고 총 8개의 마이크로프로세서로 40채널을 분산 제어하도록 구성하였다. 또한 외부와 통신을 하고 사용자로부터의 명령을 각각의 마이크로프로세서에 전달하기 위한 마이크로프로세서를 추가하였으며, 출력되는 광 신호의 세기를 측정하여 VOA를 제어하는데 있어서 VOA 출력에서 바로 PD(Photo Detector)로 입력하여 AWC(Arrayed Waveguide Grating) 출력에서 광 신호를 다시 분파하여 PD에 입력하는 번거로움을 개선하였다.

• Nuclear Engineering and Technology
• /
• v.52 no.12
• /
• pp.2847-2851
• /
• 2020

A simple water level measurement method based on wavelength division multiplexing (WDM) is proposed and demonstrated. The measurement principle is based on the change of Fresnel reflection occurring at the end facet of the optical fiber tip (OFT). To increase the spatial resolution of water level sensing, a broadband light source (BLS) and an arrayed waveguide grating (AWG) are employed. The OFTs are multiplexed with the dedicated wavelength channels of AWG. By measuring all of the reflection powers reflected at the OFTs with a proposed on-site reflectometer, the water level can be monitored continuously for a fast emergency response. Moreover, it can be implemented easily with the commercially available optical components and devices with the simple configuration.

• ETRI Journal
• /
• v.35 no.5
• /
• pp.786-796
• /
• 2013

In this paper, we propose a hybrid time-division multiplexing and dense wavelength-division multiplexing scheme to implement a cost-effective and scalable long-reach optical access network (LR-OAN). Our main objectives are to increase fiber plant utilization, handle upstream and downstream flow through the same input/output port, extend the reach, and increase the splitting ratio. To this end, we propose the use of an arrayed waveguide grating (AWG) and an erbium-doped fiber amplifier (EDFA) in one configuration. AWG is employed to achieve the first and second objectives, while EDFA is used to achieve the third and fourth objectives. The performance of the proposed LR-OAN is verified using the Optisystem and Matlab software packages under bit error rate constraints and two different approaches (multifiber and single-fiber). Although the single-fiber approach offers a more cost-effective solution because service is provided to each zone via a common fiber, it imposes additional losses, which leads to a reduction in the length of the feeder fiber from 20 km to 10 km.

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

• ETRI Journal
• /
• v.38 no.1
• /
• pp.9-17
• /
• 2016

We demonstrate a time- and wavelength-division multiplexed passive optical network system employing a vertical-cavity surface-emitting laser array-based optical line terminal transceiver and a tunable bidirectional optical subassembly-based optical network terminal transceiver. A packet error-free operation is achieved after a 40 km single-mode fiber bidirectional transmission. We also discuss an arrayed waveguide grating, a photo detector array based on complementary metal-oxide-semiconductor photonics technologies, and low-cost key devices for deployment in access networks.

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