M.C. Chia

Bio: M.C. Chia is an academic researcher from University of Strathclyde. The author has contributed to research in topics: Burst switching & Optical switch. The author has an hindex of 7, co-authored 8 publications receiving 1017 citations.

Buffering in optical packet switches

Abstract: This paper consists of a categorization of optical buffering strategies for optical packet switches, and a comparison of the performance of these strategies both with respect to packet loss/delay and bit error rate (BER) performance. Issues surrounding optical buffer implementation are discussed, and representative architectures are introduced under different categories. Conclusions are drawn about packet loss and BER performance, and about the characteristics an architecture should have to be practical. It is shown that there is a strong case for the use of optical regeneration for successful cascading of these architectures.

WASPNET: a wavelength switched packet network

Abstract: WASPNET is an EPSRC-funded collaboration between three British Universities: the University of Strathclyde, Essex University, and Bristol University, supported by a number of industrial institutions. The project which is investigating a novel packet-based optical WDM transport network-involves determining the management, systems, and devices ramifications of a new network control scheme, SCWP, which is flexible and simplifies optical hardware requirements. The principal objective of the project is to understand the advantages and potential of optical packet switching compared to the conventional electronic approach. Several schemes for packet header implementation are described, using subcarrier multiplexing, separate wave lengths, and serial transmission. A novel node design is introduced, based on wavelength router devices, which reduce loss, hence reducing booster amplifier gain and concomitant ASE noise. The fabrication of these devices, and also wavelength converters, are described. A photonic packet switching testbed is detailed which will allow the ideas developed within WASPNET to be tested in practice, permitting the practical problems of their implementation to be determined.

Packet loss and delay performance of feedback and feed-forward arrayed-waveguide gratings-based optical packet switches with WDM inputs-outputs

Abstract: This paper analyzes the packet loss and delay performance of an arrayed-waveguide-grating-based (AWG) optical packet switch developed within the EPSRC-funded project WASPNET (wavelength switched packet network). Two node designs are proposed based on feedback and feed-forward strategies, using sharing among multiple wavelengths to assist in contention resolution. The feedback configuration allows packet priority routing at the expense of using a larger AWG. An analytical framework has been established to compute the packet loss probability and delay under Bernoulli traffic, justified by simulation. A packet loss probability of less than 10/sup -9/ was obtained with a buffer depth per wavelength of 10 for a switch size of 16 inputs-outputs, four wavelengths per input at a uniform Bernoulli traffic load of 0.8 per wavelength. The mean delay is less than 0.5 timeslots at the same buffer depth per wavelength.

Optical packet switches: a comparison of designs

Abstract: Many optical packet switches have been proposed to facilitate the widespread deployment of broadband integrated services digital networks. Although optical packet switches offer data rate and format transparency, and high switching speed, their performance strongly depends on optical device technology. This paper discusses the fundamental limitations of a selected number of guided wave optical packet switches; a comparison in terms of the number of components, buffering capability, control complexity and switching technology is made. The main limitation of these optical packet switches is optical splitting/combining loss. One approach to reduce this loss is the use of arrayed-waveguide gratings (AWGs). An AWG having a crosstalk level as low as -30 dB can be used as a demultiplexer, a multiplexer and an interconnect. An AWG is proposed as the core of an optical packet switch.

Performance of feedback and feedforward arrayed-waveguide-gratings-based optical packet switches with WDM inputs/outputs

Abstract: Optical packet switches offer high speed, fine granularity, flexibility and transparency to data rate and format. There has been much work on the design of optical packet switches each having distinct advantages and disadvantages. Nevertheless, their common limitation is optical splitting loss, which is compensated by optical amplifiers, further degrading performance because of the induced amplifier noise. Hence, it is desirable to design an optical packet switch with a low optical splitting loss. This study has focused on the ALCATEL broadcast-and-select switch, which has significant optical splitting and combining losses for large switches. Arrayed-waveguide gratings (AWG) have been chosen to reduce the switch splitting loss replacing the demultiplexers and Semiconductor Optical Amplifier gates (SOA gates) in the ALCATEL switch. The switch still has the same functionality with an AWG which can be used as an interconnect, and has been demonstrated with insignificant crosstalk of approximately 30 dB. In this paper, three optical packet switches using AWGs are studied; the broadcast-and-select switch, the feed-forward delay switch and the feed-back delay switch. An additional novel feature is their use of wavelength division multiplexed inputs and outputs. Here, their optical performance is investigated with respect to bit error rate and power penalty, and compared with the ALCATEL broadcast-and-select switch using SOA gates.

Advances in photonic packet switching: an overview

Abstract: The current fast-growing Internet traffic is demanding more and more network capacity every day. The concept of wavelength-division multiplexing has provided us an opportunity to multiply network capacity. Current optical switching technologies allow us to rapidly deliver the enormous bandwidth of WDM networks. Photonic packet switching offers high-speed, data rate/format transparency, and configurability, which are some of the important characteristics needed in future networks supporting different forms of data. In this article we present some of the critical issues involved in designing and implementing all-optical packet-switched networks.

Nonlinear Optics for High-Speed Digital Information Processing.

Abstract: Recent advances in developing nonlinear optical techniques for processing serial digital information at high speed are reviewed. The field has been transformed by the advent of semiconductor nonlinear devices capable of operation at 100 gigabits per second and higher, well beyond the current speed limits of commercial electronics. These devices are expected to become important in future high-capacity communications networks by allowing digital regeneration and other processing functions to be performed on data signals “on the fly” in the optical domain.

Optical Packet and Burst Switching Technologies for the Future Photonic Internet

Abstract: This paper reviews advanced optical burst switching (OBS) and optical packet switching (OPS) technologies and discusses their roles in the future photonic Internet. Discussions include optoelectronic and optical systems technologies as well as systems integration into viable network elements (OBS and OPS routers). Optical label switching (OLS) offers a unified multiple-service platform with effective and agile utilization of the available optical bandwidth in support of voice, data, and multimedia services on the Internet Protocol. In particular, OLS routers with wavelength routing switching fabrics and parallel optical labeling allow forwarding of asynchronously arriving variable-length packets, bursts, and circuits. By exploiting contention resolution in wavelength, time, and space domains, the OLS routers can achieve high throughput without resorting to a store-and-forward method associated with large buffer requirements. Testbed demonstrations employing OLS edge routers show high-performance networking in support of multimedia and data communications applications over the photonic Internet with optical packets and bursts switched directly at the optical layer

Slow-light optical buffers: capabilities and fundamental limitations

Abstract: This paper presents an analysis of optical buffers based on slow-light optical delay lines. The focus of this paper is on slow-light delay lines in which the group velocity is reduced using linear processes, including electromagnetically induced transparency (EIT), population oscillations (POs), and microresonator-based photonic-crystal (PC) filters. We also consider slow-light delay lines in which the group velocity is reduced by an adiabatic process of bandwidth compression. A framework is developed for comparing these techniques and identifying fundamental physical limitations of linear slow-light technologies. It is shown that slow-light delay lines have limited capacity and delay-bandwidth product. In principle, the group velocity in slow-light delay lines can be made to approach zero. But very slow group velocity always comes at the cost of very low bandwidth or throughput. In many applications, miniaturization of the delay line is an important consideration. For all delay-line buffers, the minimum physical size of the buffer for a given number of buffered data bits is ultimately limited by the physical size of each stored bit. We show that in slow-light optical buffers, the minimum achievable size of 1 b is approximately equal to the wavelength of light in the buffer. We also compare the capabilities and limitations of a range of delay-line buffers, investigate the impact of waveguide losses on the buffer capacity, and look at the applicability of slow-light delay lines in a number of applications.

All-optical label swapping networks and technologies

Abstract: All-optical label swapping is a promising approach to ultra-high packet-rate routing and forwarding directly in the optical layer. In this paper, we review results of the DARPA Next Generation Internet program in all-optical label swapping at University of California at Santa Barbara (UCSB). We describe the overall network approach to encapsulate packets with optical labels and process forwarding and routing functions independent of packer bit rate and format. Various approaches to label coding using serial and subcarrier multiplexing addressing and the associated techniques for label erasure and rewriting, packet regeneration and packet-rate wavelength conversion are reviewed. These functions have been implemented using both fiber and semiconductor-based technologies and the ongoing effort at UCSB to integrate these functions is reported. We described experimental results for various components and label swapping functions and demonstration of 40 Gb/s optical label swapping. The advantages and disadvantages of using the various coding techniques and implementation technologies are discussed.