Light Wave & Electronics

Internationally, telecommunications is under-going major rapid change brought about by regulatory changes, increasingly open markets and technological advances in integrated circuits, optical devices, and computer systems.                                        

The convergence and the integration of these technologies, coupled with the driving factors of faster transmission speeds, lower signal levels, and denser circuit boards has made managing signals in electronic and communication switching systems more critical. These driving factors has placed a greater emphasis on managing problems relating to signal integrity, timing distribution, timing jitter, signal distribution, noise, asynchronism, and cross-talk.

In long-haul transmission domain, optical amplifiers together with wavelength-division multiplexed have revolutionized high speed data transmission by providing flexible and cost-effective means of amplifying and processing of signals almost entirely in the optical domain independent of data rate and protocols. However, the gain provided by the optical amplifiers is affected by changes in the input power operating power of the various channels carried by a link. The gain dynamics are also function of the number of cascaded amplifiers. Local control of pump power in each amplifier and also distributed control strategies are necessary to achieve good end to end optical link performance.

WATRI has core strengths in a number of research areas that underpin electronic and optical systems employed in communications areas. This includes research on synchronisation, jitter generation, jitter filtering, optical amplifier control algorithms, laser drivers and high performance optical monitoring circuits, and statistical modelling of noise in electronic systems. These core strengths have enabled the WATRI to bid and secure R&D contracts, to develop courses for industry and degree programs and ensure relevance of implementation dependent R&D within its programs.

The objectives of the electronics program are:
          - To maintain a strong generic research base in areas that underpin the high speed digital systems;
          - To demonstrate knowledge developed in the basic and applied research areas;
          - To focus activities on producing new products or devices, installing new processes, systems or services,
            or substantially improving current technologies;
          - To use the WEB as a delivery mechanism in the technology transfer of know-how through online courses
            and tutorials.

Design for Signal Integrity, Design for EMC Compliance, Digital/RF Design, Analogue RF Design, ASIC/FPGA design, Gigabit/s Interconnections, Electronics for Optical Amplifiers, Low Noise design, Low Phase Noise Design, Multilayer PCB Design, Power Distribution Design for High Speed Mixed Mode Systems, Timing & Synchronisation Circuits, Digital Frequency Detectors, Analogue and Digital Phase Locked Loops. DSP Systems, Device Simulation, Analogue Simulation, Control System Simulation, PCB Structures.

Control Systems for Optical Amplfiers

The Control Systems for Optical Amplifiers research project will initially focus on a specific optical amplifier structure known as an Erbium-Doped Fibre Amplifier (EDFA). An EDFA is an in-line laser amplifier structure that can be used to boost signals travelling along an optical fibre. While the steady-state characteristics of EDFA's are now well understood, the transient dynamics of these non-linear devices present considerable challenges in the design of high-performance optical communications systems. Frequent power transients at the input to the EDFA, resulting from channel failure or network reconfiguration for example, can significantly impair the remaining propagating channels.

This project will address the following core areas in EDFA control system design:
          - Dynamic control strategy and implementation;
          - Laser drive and monitoring electronics hardware;
          - Software control algorithms.

In recent years, involvement in the form of industry contracts with Altamar Networks, California, has enabled WATRI to gain considerable experience in the design and implementation of the sophisticated electronics hardware and software necessary to control the optical components of a high-performance EDFA. This project will also draw on WATRI's substantial strengths in system modeling and analysis; computer simulation; high-performance analogue electronics design and embedded real-time systems.                              

Recently Altamar generously released one of its state-of-the-art EDFA-based optical amplifiers (shown below) to WATRI. This substantial contribution to the ATcrc's laboratory will provide the means for:
          - Validation of theoretical EDFA models and computer simulation results;
          - Prototyping of new control algorithms.

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Timing Impairments in Electronic Systems

Simulation.

Experimental Verification.

Impairments suffered by timing signals play a critical role in electronic systems. They limit the dynamic range of an analog-to-digital converter, the throughput of a digital bus, affect the behaviour of digital synchronisers, influence the bit error ratio of a communications link, and determine the sensitivity and selectivity of radio receivers. Timing impairments are the result of random noise and systematic disturbances within electronic devices and interconnections.

To identify the mechanisms that contribute most to timing impairments induced on signals processed by electronic amplifiers, FPGAs and interconnects; and to develop models suitable for predicting performance and for developing optimal designs. Examples of applications that will be targeted include printed-circuit-board level clock distribution for telecommunication systems, and clock recovery circuits using FPGA based digital designs. Within this project, two major tasks and relevant milestones have been identified: Phase Noise Modelling Objective - Develop the underlying mathematical foundation for the method of phase noise modeling previously successfully applied to signal stage RF amplifiers. Apply the model to multi-stage circuits. Clock Jitter Objective - Study the effect of FPGA and discrete logic elements on clock jitter and develop techniques for minimising jitter. Since the power supply can be a significant contributor to timing impairments in electronic systems, research on the design of power supply distribution systems is also being pursued.

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Key Personnel

Key personnel are:

Prof Kevin Fynn, CEO, WATRI

Prof Antonio Cantoni, Research Director, WATRI