Peter Raymond Ball

Performance of the passive recirculating fiber loop buffer within an OTDM transmission link

In this paper, we examine the propagation of both standard soliton and the Gaussian-soliton shaped pulses within a recirculating fiber loop buffer. We believe that this is the first time Gaussian-soliton pulses are considered for the transmission of OTDM signals within a communication system. The simulation model is based on the nonlinear Schrodinger equation (NLSE) and accounts for fiber loss within the communications channel. At this stage pulse interactions are not considered and direct modulation of the launched pulses is assumed. Simulation results for bit error rate (BER) performance at different buffer loop numbers and eye diagrams for buffered and unbuffered cases are presented.

Simulation of all-optical time division multiplexed router

In this paper we have developed a model of an all optical router based on the terahertz optical asymmetric demultiplexer (TOAD). The model architecture is based on a system which has as its input on OTDM packet containing header and payload information. The model simulates extraction of header information from the data stream using one TOAD, which is subsequently used to make a routing decision. The payload information is routed through a second TOAD according to the information contained in the header.

Modelling the response of different WDM PON architectures to varying traffic load

The introduction of wavelength division multiplexing into the access network is a potentially attractive alternative upgrade strategy to increasing the bit rate of passive optical networks (PON). A number of different methods have been proposed to implement a multi-wavelength PON and hence a careful assignment needs to be made of the most cost effective, both in the short term and for future increases in capacity. One key issue is the use of dynamic allocation of wavelengths, which allows the reconfiguration of the network in response to network demand. A model has been produced to simulate demand patterns on a PON, in order to quantify the benefits of dynamic assignment.

Performance analysis of all-optical time division multiplexed router based on terahertz optical asymmetric demultiplexer

Growing demands for bandwidth have stimulated the development of high-speed optical shared media networks. At present, most research on optical networking has concentrated on wavelength- division multiplexing (WDM). Optical time-division multiplexing (OTDM) is considered as an alternative to WDM offering data rates greater than 100 Gb/s using just a single wavelength. In such systems all optical routers, which overcomes the bottleneck of optoelectronic conversion, play an important role. This paper investigates TOAD based 1 X 4 optical router by developing a mathematical model. The proposed model is simulated and results for crosstalk are presented and compared with 1 X 2 router.

Buffering optical IP packets

A novel buffering mechanism for IP packets over WDM links is proposed by exploiting the packet nature. ACK packets which do not carry any payload can be singled out to be processed and stored purely in the electronic control plane without getting through the optical path which consists of the switching matrix and optical delay line buffers. An optical path is then reserved at the output for these ACK packets by extending the optical delay lines to be integral of ACK packets. Simulation results have shown an improvement both in the packet loss probability and the mean delay for using this scheme.

Simulation of the passive recirculating fiber loop buffer

The current trends within ultra high-speed optical time division multiplexed (OTDM) based communication systems dictate the increasing need for all optical buffering systems. Such systems inherently avoid the bottlenecks associated with opto-electrical (O/E) and electro-optical conversions (E/O)1. These buffers would enable the storage of data for discrete time intervals, and are necessary for many OTDM applications. Storage time limitations within passive recirculating fiber loop buffers are mainly due to the dispersive, nonlinear and loss properties of the fiber. These result in both amplitude decay and pulse spreading which may have a detrimental effect on data integrity. In this paper, we examine the propagation of both standard soliton and Gaussian-soliton shaped pulses within a recirculating fiber loop buffer. The simulation model is based on the nonlinear Schrodinger equation (NLSE) and accounts for fiber loss within the communications channel. At this stage pulse interactions are not considered and direct modulation of the launched pulses is assumed. Simulation results for bit error rate performance at different buffer loop numbers is presented.