Papers by Keyword: WDM

Abstract: Research of FBG temperature sensing network base on WDM combined with spatial division multiplexing. Theoretical analysis and numerical simulation proves that the scheme is feasible, and the system has relatively higher measuring accuracy, which realizes the temperature dynamic measurement in large space, forming temperature sensing network.

Abstract: A WDM optical access network architecture based on double-fiber-tangent rings is proposed. With the proposed architecture, both data convergence and link protection can be realized. OLT and RNs can automatically switch to protection mode to overcome fiber failure occurring no matter in both primary ring (PR) and sub-ring (SR). The RNs designed as tangent points can realize wavelengths adding and dropping between PR and SR, and they also can realize network expansion through adding more wavelengths. In addition to this, the design of double-fiber ring can better the survivability and self-healing ability of the network.

Abstract: We know that Inter-satellites communica-tion is a very important to us.However, real global coverage can only be achieved by satellite systems. Satellites communication is the most important mean of the communication network. The traditional satellites communication and inter-satellites links are built by microwave. Recent years, laser links for inter-satellites communication are becoming more and more important.

Abstract: Hybrid optical OFDM/WDM system is proposed to provide longer reach and larger capacity comparing with existing PON systems in order to meet the ever increasing bandwidth demand and data rate of next generation optical access networks. In this paper, two channels using different modulation at 10 Gb/s are used for downstream link. OFDM signals occupy different portions of the available signal spectrum for signal transmissions by using WDM. As a result, the system has good performance based on SNR with 50 km distance and QAM modulation delivers better performance compared with PSK.

Abstract: This article discusses the Image Transmission Board which based on Virtex-5 FPGA, it achieved PC transmission data through PCIE Bus. This system refers to the example of DMA transmission which provided by XILINX company, it use DDR2 memory to cache data. This board could provide Windows system use WDM driver to interact with hardware resources. The data transmission rate of FPGA is 1.5Gbit/s

Abstract: In this work, we study the problem of efficient traffic grooming using light-trail. In case of lightpath a complete wavelength is dedicated between source and destination node. Once a lightpath is set up, the entire wavelength is used exclusively by the source-destination node pair. Data cannot be transmitted or received by nodes along the lightpath except the starting and ending node. However, it is often observed that the bandwidth requirement in today’s network is often varying and does not justify the need for allocating an entire wavelength for a single data transmission. Therefore, the wavelength capacity may be underutilized. Then the term light-trail came into existence, it was proposed to avoid the inability of intermediate nodes to use a connection wavelength. In this work, we have proposed a traffic grooming algorithm to maximize the network throughput for wavelength-routed mesh networks using static light-trail. The efficiency of our approach has been established through extensive simulation on different sets of traffic demands with different bandwidth granularities for different network topologies and compared the approach with existing algorithm.

Abstract: In this paper a hybrid optical code division multiple access (OCDMA) over wavelength division multiplexing (WDM) network is proposed to support large number of subscribers. The system combines two different techniques, namely OCDMA and WDM for supporting many subscribers simultaneously. We used modified double weight (MDW) codes as a signature address in designing the system because this code can accommodate more number of simultaneous active users under considerable standard bit error rate (e.g. ≤ 10-9). The induced MDW code for hybrid system can eliminate multiuser interference fully and increase the bit-error-rate performance compared to other codes at the same time. We ascertained by simulation results that the proposed scheme provides very good performance and enhance the network capability. Therefore, this system can be considered as a promising solution for the next generation optical access network.

Abstract: In recent years, optical network has made great progress. Optical networking architects were concerned with medium access control protocols for optical switching, the combination of wavelength conversion, and optimum forms of network. How to apply the simple high-speed transfer function of the optical network node to the IP network is an important issue in achieving an IP and optical integrated network. In this paper, we present a new node structure which has a new function. Adding new nodes to a optical network based on this new design, we can make a connection to different network. It is important to provide solutions for various requirements such as integrated optical network scalability and support for various types of networks in an optical network.

Abstract: In this paper, a new routing design is presented. Interior gateway Protocols (IGPs), particularly Open Shortest Path First (OSPF), uses a simple single metric component, cost, which is based on the bandwidth of the link. Most large IP networks run Interior Gateway Protocols (IGPs) such as Open Shortest Path First (OSPF) or Intermediate System-Intermediate System (IS-IS) that select paths based on static link weights. Enhanced Interior Gateway Routing Protocol (EIGRP) is slightly more aware of the link characteristics in that it calculates a metric based on cumulative delay (delay is simply an arbitrary assigned value) and the minimum bandwidth value encountered between the source and destination. Routing technology can better the network operation efficiently.

Abstract: This paper investigates the defects that exist in the blocking probability and the cost of establishing light-tree in the multicast routing algorithm with sparse splitting capability constraint based on the Virtual Source (VS). It proposes a new multicast routing algorithm N_VSBA (New Virtual Source Based Algorithm). By introducing the minimum interference routing algorithm in the path calculation among the VS nodes, this new algorithm solves the problem of blocking caused by establishing the light-tree through a pre-computed path when two VS nodes concentrate. This algorithm also solves the problem of VS-based algorithm’s not being able to utilize the TaC (Tap and Continue) capability of indecomposable optical nodes by introduction of MPH (Minimum Path-cost Heuristic) algorithm into the process of adding light-tree into indecomposable nodes. Simulation results show that the new algorithm has improvements of different degrees in aspects of blocking probability, average number of wavelength links and average maximum number of wavelength.