Iain Skinner

Solitons in a nonlinear optical coupler in the presence of the Raman effect

Abstract Using both an approximation and numerical simulations, we examine solitons in a dual-core nonlinear optical fiber in which the Raman effect acts. We find that the Raman effect restabilizes the symmetric soliton at large energies. It also allows quasi-stable asymmetric solitary waves to exist at smaller energies.

Embedding Academic Literacy Support Within the Electrical Engineering Curriculum: A Case Study

This paper reports the integration of supplementary training in academic literacy, for those without the assumed entry standard, into a standard electrical engineering program without compromising any other educational objectives. All students who commenced an engineering degree were tested as part of their first sessions assessment activities. Those identified as having inadequate academic literacy were directed to study a specifically designed credit-bearing course, which is controlled by the engineering faculty but was designed and is taught in collaboration with academic literacy teachers. Students who completed this course responded positively and also demonstrated measurable improvement in their communication skills. The approach has alleviated the skepticism about teaching academic literacy usually found amongst engineering faculty staff and has been adopted by the wider engineering faculty.

A novel wide-angle low-loss dielectric slab waveguide Y-branch

A new Y-branch structure for dielectric waveguides is proposed and analysed using simple geometrical optics and beam propagation methods. It is shown both qualitatively and quantitatively that the proposed structure has larger branching angles but lower radiation loss than those associated with either conventional Y-branches or structures with antenna coupled and phase front accelerators. The optimal design parameters calculated by numerical simulations are in very good agreement with those found from the geometrical optics. The simulations also reveal that the performance is fairly insensitive to fabrication errors. >

Soliton switching in a variable nonlinear coupler

Abstract Coupling and switching of solitons in a nonlinear coupler whose coupling varies with longitudinal distance is examined. Within the variational approximation, an exact solution which describes complete coupling is found. The accuracy of this approximation is shown to be good.

Time-domain soliton filter based on a semidissipative dual-core fiber

We propose a time-domain dual-core fiber filter that greatly reduces soliton jitters and noise power in its application to ultrahigh-speed soliton communication systems. This filter is simply a dual-core fiber that has one core with negligible loss and the other with large loss.

Effective index models for MQW waveguides

Abstract It is shown that a three-layer, step-index model can be used to describe propagation of both TE and TM modes within MQW waveguides but that the two mode types “see” different effective indices in the central layer.

Enhanced switching speeds observed at 980 nm in neodymium-doped twin core fiber, using stimulated down-pumping at 1060 nm

In this presentation, preliminary observations and measurements of increased switching speeds in resonantly enhanced nonlinear systems are shown. The method uses stimulated down- pumping of the 4F3/2 metastable state in neodymium, but is applicable to any four- level system, or pseudo-four-level system such as erbium. Since the stimulated down-pumping is only initiated at the end of each switching period, the lifetime of the metastable state is not affected. Thus high up-pumping efficiencies are still possible. This allows both low power operation and fast relaxation to be achieved in the same switching system. The relaxation time has been reduced from approximately 390 microsecond(s) to less than 120 microsecond(s) , and it is shown that the reduction is dependent on the power of the down-pumping source.

Effect of language difficulties on results of engineering students

Weak language ability has a deleterious effect on a students academic performance. This paper reports an attempt to assess how big this effect might be for engineering students. We found that there is a measurable effect - in this case, as big a difference as 17 marks out of 100 - that could be ascribed to language skills. However, it is not clear what fraction of this mark deficit is language and what fraction is due to related issues such as culture.

Do ethics courses make engineering students more ethical

To decide whether teaching ethics improves the ethical reasoning of engineering students, an online survey was used to assess their ethical reasoning before and after taking a course in which ethics is taught. Students were asked to consider scenarios requiring ethical judgment and their preferences for pre-conventional, conventional and post-conventional reasoning were measured. Overall, students taking the course with the most emphasis on activities related to ethics showed small but significant movement away from pre- and towards post-conventional reasoning. Local and international and male and female results were compared.

Senior students as peer-teachers in laboratory classes: Impacts and insights

This paper reports on the pathway for selecting and supporting casual laboratory demonstrators (teaching assistants) in undergraduate electrical engineering programs, and the outcomes that came with this systematic approach. In particular, many more senior undergraduate students were employed, to complement the research students, in the role of laboratory demonstrators. The success of the program relied on a centralized approach for selection, allocation, and training of the demonstrators. This explains how the changes led to better interest by senior undergraduates in the job of demonstrator, and the benefits of such staff being peer-teachers, notably those of both peer-to-peer learning and structured mentoring. It also explores the effect of the employment on the senior students.