In this paper, the three ameliorated new coding schemes of the Super-FEC (Forward Error Correction) concatenatedcodes
(namely, the inner-outer concatenated-code, the parallel concatenated-code and the successive concatenated-code
with interleaving) are proposed after the development trend of high-rate optical transmission systems and the defects of
the FEC codes in the current optical transmission systems have been analyzed. The system simulation of the inner-outer
concatenated-codes is implemented and the schemes of encoding/decoding the parallel concatenated-codes are proposed.
Furthermore, the two successive concatenated-codes with interleaving of the RS(255,239)+RS(255,239) code and the
RS(255,239)+RS(255,223) code are simulated, and the analyses for the simulation results show that the two successive
concatenated-codes with interleaving, compared with the classic RS (255,239) code and other codes, are a superior code
type with the advantages of the better correction error, moderate redundancy and easy realization. And their net coding
gains (NCG) are respectively 1.5dB, 2.5dB more than that of the classic RS(255,239) code at the BER (Bit Error Rate) of
10-12. At last, based on the ITU-T G.709, the frame format of the new concatenated-code on applying in high-rate optical
transmission systems is proposed and designed, this lays a firm foundation in order to design its hardware in future and
pioneers a direction in its physical application.
LPFGs written by high-frequency CO2 laser pulses have great potential for use in optical fiber sensing and communication. It is of importance to study the fundamental characteristics of these novel LPFGs. In this paper, a more systematic analysis is carried out to investigate the resonant wavelength-bend sensitivity of the LPFG and its bend loss of resonant peaks based on the mode field theory. It is for the first time to our knowledge, that a method is proposed for analysis of the bend orientation-dependence of the LPFG. The simulation is in agreement with experimental results. This paper provides a more systematic analysis for the bending characteristics analysis of the LPFG written by the high-frequency CO2 laser pulses exposure method.
Two schemes of linear combinatorial code (LCC) coding scheme with different and multiple wavelength bandwidth were proposed using fiber grating cascades in series and parallel, respectively. The system model and probability density function are investigated. Numerical simulation confirmed that bit error ratio (BER) performance largely improved due to that of sub-codeword system. Moreover, the preference of LCC with different wavelength bandwidth is better than that of multiple wavelength bandwidth.
A novel wavelength-time differential code division multiple access system is proposed for multirate transmission. The system model is given and analyzed. Differential detection can be adopted by assigning two orthogonal codes for one user and using these two codes to encode “1” and “0” with different period, respectively. When one-branch and zero-branch are balanced perfectly, the system can reduce the noise of background, thermal, dark current, and multiple access inference. Moreover, by varying the ratio of number of bit ”1” and bit “0” in data steaming, the multirate data stream transmission is achieved.
Different ways of showing display holograms to students are introduced in this paper, including: (1) Showing display holograms to the class in the classroom. (2) Showing display holograms to the individual students. (3) Visiting display hologram exhibitions. (4) Making and showing hologram Jpeg/Mpeg movie clips on the screen. (5)
Making and showing hologram Quicktime movie clips. (6)Making and showing movie clips for students to study basic holography principles. More than 10 movie clips are made for showing display hologram principles in classroom.
In the NGI featuring grid technology, as a foundation of grid Meta-Computing grid node must have large capability of data storage and processing. In this paper, parallel processing and computing environment for Multi-CPU and Multi-MEM is researched, the main part as follows.
Part 1.optical routing-switching system design
a. Adopting CWDM to realize interconnection for parallel high capability computers whose parallel scale are less than 16. The advantages are network simplification, lessening cross talk, reducing cost and have nothing to do with single computer.
b. We take IP packet format to be data transmission format to match today’s Internet, being efficient and making it compatible with each other.
c. Researching Odd-Even merging network to build OXC routing system. We have done the optimizing analysis of the number of optical switches needed in different parallel systems, designing routing control system featuring centralization and inside control.
Part 2.optical routing-switching protocol design and simulation
This paper designs switching protocol of Multi-CPU and Multi-MEM parallel processing system. The protocol can control different wavelength signals to route and switch effectively. Simulation shows that it can reduce probability of block and reach the requirement of data transmission.
Recently, people pay more attention to the grid technology. It can incorporate high-speed network, high performance computer, large database, sensor and remote equipment etc. Moreover, it can not only connect all kinds of resources in the network and also put them into a super transparent computing environment for customers. In which it can realize meta-computing for the shared resources. However, traditional parallel computing system such as SMP and MPP use multi-processors to upgrade computing by closed coupler. Doing like that, the flexible and scalable performance of the system will be limited so that the system can't meet the requirement of the grid technology.
In this paper, the architecture of cluster computing system applying in grid nodes is introduced. It mainly includes the following aspects. First, the network architecture is analyzed and designed. Second, it forms virtual computers with distributing computing including divided computing and shared computing. Last, it discusses the communication problems between the grid nodes. In other words, it discusses the realization of single map in order to meet all the requirements of customers sent to the grid nodes.
In this paper,architecture of grid audio/video communication environment based on optical layer multicast is introduced. First, architecture of optical layer multicast communication environment is analyzed. Then, scheme of large capability optical routing is presented. Last, condition of non-blocking multicast communication over WDM(wavelength division multiplexing) grid network is analyzed.
As many kinds of media converge to the Internet, the backbone will face new demands not only in terms of bandwidth, but also in terms of services. Therefore it is certain that Internet will evolve into IP-over-WDM based all-optical network. Obviously, the optical router will be a crucial network device. In the paper, we propose a practical architecture of optical router. Based on all-optical labeled burst switching, this architecture supports all-optical edge-to-edge data routing and transport services with transparent data rate and format, and simplifying protocol and operations. From the viewpoint of practicality, some key issues during the design have been studied and analyzed, and corresponding feasible solutions to them are put forward respectively. Finally an experimental system and results are shown.
As the Internet traffic exponentially growing, the next generation IP network is forced to scale far beyond its present performances. The more and more mature optical switching technology, such as optical burst switching, is expected to provide an ideal infrastructure for meeting the demands. However in optical switching, there is one critical issue, namely contention, which roots from multiple optical data requesting the same output port How to resolve contention in optical domain will have a significant effect on the performance (in terms of the burst-loss rate, average delay time and network throughput) of optical switching network. The paper proposes a contention resolution scheme based on FDL, AWG and TWC. Here FDL is used as two functions, i.e. forwarding and feedback for smaller or longer buffering time requirements respectively. In the paper we incorporate the scheme into the design of optical switch. We descript the optical data buffering strategy when contention occurs. We also study the performance of the scheme in a Markov process model under the assumption of uniform Bernoulli traffic, and validate the analysis through numerical simulation. The computer simulation results show that the scheme can efficiently use FDL buffering and AWG switching capacities, hence can obviously reduce the contentions.
This paper has reported the research of a scalable wavelength division multiplexing (WDM) optical routing system applied to the interconnection between CPU and MEM of distributed parallel computer. This system is built on DWDM and the optical switch array, which can connect CPUs and MEMs in a multigigabit WDM fiber, and so take advantage of high throughput, low-latency, error-free parallel transmission. And the paper has analyzed the performances degradation arising from super-speed and multi-wavelength, and put forward practical improvement measures. Furthermore the paper has designed a dual-window DWDM experimental system, and tested the data exchange between CPU and MEM. The purpose of this paper lies in exploring an optical WDM interconnection routing system which can not only be super-capacity, and reduce the complexity in implementation technologies, and also optimize the internal structures, or even external communication mechanisms of parallel computer.
Along with progresses in high-speed, broadband long-haul and full service transmission in optical fiber system, the polarization mode dispersion has become one of major limiting factors in terms of the system bandwidth and the linearity, and leads to severe signal impairments, especially the second-order PMD for an analog system. Therefore the purpose of the paper is to present a detailed description of PMD effects (in terms of composite second-order) on PAL-D 60 channels analog CATV signals and to show the numerical simulations about some important relations between the CSO and the PMD distortion factors. Based on the simulation results, we also discuss a second-order PMD compensation scheme for optical DWDM CATV backbone network, which can efficiently reduce second-order, or even higher-order nonlinear distortions. It has been successfully applied to our national CATV networks.
In this paper, Dispersion compensation and nonlinear distortion analysis in telecom and CATV co-network transmission
systems supported by the China Ministry of Information Industry are reported. This paper investigates: 1) the impact of
dispersion compensation fiber (IDCF) on fiber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) and
different dispersion compensation schemes, 2) the complex impact on the total nonlinear distortion induced by EDFA gain
tilt and the light source. As a result, an optimal dispersion compensation scheme and EDFA negative gain tilt are suggested
as a solution to dispersion compensation and self-compensation of the nonlinear distortion.
A practical co-network transmission system of Telecom and CATV over installed Telecom network is designed. The system, making use of WDM and other technologies, has undergone experiments and performance tests on the Public Switched Telephone Network, which illustrate that optical fiber telecommunication network could be thereby transformed into a unified broadband network integrating VOICE, DATA, and VEDIO expeditiously and conveniently.