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1.
In order to relax alignment tolerances on single-mode fiber interconnection, we propose an end face treatment to realize an expanded mode fiber. This new technique consists of splicing fibers with various lengths and characteristics. The spot size and coupling properties are analyzed numerically considering the effects of gap, offset, and tilt. Low loss, wide misalignment tolerances, and low cost are achieved. The fabrication process and experiment results are presented. The performance of a connector with this expanded fiber is reported. 相似文献
2.
Gambini P. Renaud M. Guillemot C. Callegati F. Andonovic I. Bostica B. Chiaroni D. Corazza G. Danielsen S.L. Gravey P. Hansen P.B. Henry M. Janz C. Kloch A. Krahenbuhl R. Raffaelli C. Schilling M. Talneau A. Zucchelli L. 《Selected Areas in Communications, IEEE Journal on》1998,16(7):1245-1259
This paper reviews the work carried out in the ACTS KEOPS (Keys to Optical Packet Switching) project, describing the results obtained to date. The main objective of the project is the definition, development, and assessment of optical packet switching and routing networks, capable of providing transparency to the payload bit rate, using optical packets of fixed duration and low bit rate headers in order to enable easier processing at the network/node interfaces. The feasibility of the KEOPS concept is assessed by modeling, laboratory experiments, and testbed implementation of optical packet switching nodes and network/node interfacing blocks, including a fully equipped demonstrator. The demonstration relies on advanced optoelectronic components, developed within the project, which are described 相似文献
3.
Elastic optical networks (EONs) based on orthogonal frequency division multiplexing (OFDM) technologies are seen as a promising solution for next‐generation optical transport networks to support the rapidly growing and heterogeneous traffic. In EONs, the elastic bandwidth allocation and modulation format agilities combined with reconfiguration capabilities pave the new way for leveraging the network efficiency. In this paper, we recast the network‐side path protection in EONs considering the opportunities and challenges enabled by the flexible operation of OFDM technologies. For the first time, we propose to take advantages of the reconfiguration capabilities of OFDM transponders for adapting to transmission condition variations when switching from the working to protection path in network‐side protection. The idea is inspired by the observation that in reach‐diverse networks, the transmission margin between the working path and protection path of a connection might be large enough, and thus, the most spectrum‐efficient modulation format for each path could be separately tailored, rather than imposed by a common one based on the worse condition as with current fixed transmission technologies. We formulate survivable transparent network designs for both dedicated and shared path protection in the form of integer linear programming model taking into account our proposal for enabling different transmission operations between working and protection mode. Numerical results based on extensive simulations on a realistic network topology, COST239, are presented to highlight the benefits of our proposal compared to conventional approaches in terms of spectrum efficiency for un‐capacitated scenarios and improvements in blocking ratio for capacitated scenarios. 相似文献
4.
In ATM networks, a user should negotiate at connection set-up a traffic contract which includes traffic characteristics and requested QoS. The traffic characteristics currently considered are the Peak Cell Rate, the Sustainable Cell Rate, the Intrinsic Burst Tolerance and the Cell Delay Variation (CDV) tolerance(s). The values taken by these traffic parameters characterize the so-called Worst Case Traffic that is used by CAC procedures for accepting a new connection and allocating resources to it. Conformance to the negotiated traffic characteristics is defined, at the ingress User to Network Interface (UNI) and at subsequent Inter Carrier Interfaces (ICIs), by algorithmic rules based on the Generic Cell Rate Algorithm (GCRA) formalism. Conformance rules are implemented by policing mechanisms that control the traffic submitted by the user and discard excess traffic. It is therefore essential to set traffic characteristic values that are relevant to the considered cell stream, and that ensure that the amount of non-conforming traffic is small. Using a queueing model representation for the GCRA formalism, several methods are available for choosing the traffic characteristics. This paper presents approximate methods and discusses their applicability. We then discuss the problem of obtaining traffic characteristic values for a connection that has crossed a series of switching nodes. This problem is particularly relevant for the traffic contract components corresponding to ICIs that are distant from the original source. 相似文献
5.
Annie Gravey Grard Hebuterne Pierre Boyer Jean-Raymond Louvion 《International Journal of Communication Systems》1989,2(4):247-252
Specific queueing models are derived in order to size the buffers of ATM switching elements in the cases of ATM or STM multiplexed traffic. Buffering is performed either at the outputs or in a central memory for ATM multiplexed traffic; for STM multiplexed traffic, buffers can also be provided at the inputs. The buffer size is chosen in order to ensure a loss probability in the switch smaller than 10?10. It is shown that the buffer size per output in the case of central queueing is smaller than the buffer size in case of output queueing for both ATM and STM multiplexed traffics. Moreover, for STM multiplexed traffic, buffer sizes are identical for input and output queueing. Lastly, it is pointed out that buffers used for STM multiplexed traffic should be 4 to 20 times larger than the corresponding buffers for ATM multiplexed traffic. 相似文献
6.
Priority management in ATM switching nodes 总被引:10,自引:0,他引:10
Kroner H. Hebuterne G. Boyer P. Gravey A. 《Selected Areas in Communications, IEEE Journal on》1991,9(3):418-427
Various space priority mechanisms and their detailed performance evaluation are described. A comparative performance study is given, indicating the excellent performance characteristics of a simple buffer management scheme called partial buffer sharing. The introduction of a second bearer capability provides a 10-6 cell loss rate instead of 10-10 相似文献
7.
Gravey Annie Amar Djamel Gravey Philippe Morvan Michel 《Photonic Network Communications》2019,37(3):278-295
Photonic Network Communications - The present paper addresses future network architectures considered for Fixed Mobile Convergence, where users can access resources transparently either through... 相似文献
8.
In this survey we present an overview of the current state-of-the-art and the future issues to be resolved for the deployment
of integrated communications networks based on the Asynchronous Transfer Mode (ATM) Our presentation is from the perspective
of traffic and congestion control and management issues which hold the key to the successful achievement of this deployment
since it is mainly in these aspects that ATM networks differ from conventional communication networks. 相似文献
9.
A beam-control system to write gratings on a holographic plane is studied. The arrangement is designed to interconnect two 1024 monomode fiber arrays. The beam-control system is composed of two subsystems: a beam steerer, which deflects one incident beam toward 1024 positions, and a collimating system, which adapts the shape of the deflected beam to the holographic plane. The collimating system was studied only after the beam steerer had been fully built and tested. It is based on the photorefractive amplification of a beamlet selected by a shutter array. The deflection efficiency is enhanced by a factor 1500 with the photorefractive crystal, and the signal-to-noise ratio is larger than 5500. The influence of the optical aberrations on the coupling losses of the infrared beams in the monomode fibers are evaluated. 相似文献
10.
Bogdan Uscumlic Annie Gravey Philippe Gravey Yvan Pointurier Michel Morvan 《Photonic Network Communications》2016,31(3):432-447
We propose a new receiver architecture for coherent detection in slotted optical packet switching rings with elastic (rate adaptive) optical transponders. Such rings are a candidate solution for future datacenter and metropolitan networks. The new receiver can detect more than a single packet per time slot and consequently has higher flexibility (translating into higher supported capacity, or, equivalently, lower end-to-end latency, or a combination or both), at the cost of a moderate increase in the transponder complexity and energy consumption (less than 10 %). We apply network planning and traffic engineering simulation tools (which we validate on small examples using theoretical models) to quantify the increase in network capacity and latency reduction that can be achieved thanks to the use of the new receivers. Finally, we identify the stability problem of the insertion process in the rings with the coherent receivers and propose a polynomial network planning algorithm, for the case of fast-tunable transmitters. We evaluate the cost of enforcing the stability, in terms of the additional transponders needed, for the mentioned case. 相似文献