Single-Course Engelsk 5 ECTS

Waveguide optics

Overall Course Objectives

To establish a solid understanding of the physical and technological background for optical waveguides and components for the control of a broad spectrum of light, from the visible to THz frequencies. Optical circuits are expected to become of great importance for future engineers within areas such as telecommunication, sensors and computer architecture. Optical fibers already play a crucial role within long-distance signal transmission, and are increasingly used as sensors, in laser systems, and for signal processing. This course gives an elementary understanding of integrated optical waveguides, optical fibers, plasmonic waveguides, simple optical components based on these, and a discussion of elementary THz technology. The course constitutes a solid platform for further work (e.g. masters projects) within these fields.

See course description in Danish

Formulate equations describing guided modes in straight and weakly bent optical waveguides, based on dielectric materials and/or metals, including the weak-guidance approximation and the scaling laws it implies.
Formulate equations describing the coupling of light into dielectric waveguides.
Describe the definition and implications of the concepts of dispersion, nonlinear coefficient/effective area, and bend loss for waveguides.
Describe the structure of guided modes and waveguiding properties in slab and rectangular waveguides, including dispersion, effective area and bend loss.
Describe the structure of guided modes and waveguiding properties in step-index fibers, including dispersion, effective area and bend loss for given values of core radius and index contrast.
Discuss structure and applications of graded-index fibers, polarization-maintaining fibers, and photonic crystal fibers.
Describe structure, guided modes, propagation loss and applications for various kind of hollow-core optical fibers.
Derive equations for reflection/transmission/mode coupling in waveguide-integrated Bragg and long-period gratings. Sketch solutions for uniform Bragg and long-period gratings, understand the meaning of chirp and apodisation.
Derive coupled-mode equations for directional couplers, and sketch their solutions. Use these results to formulate transmission equations for Mach-Zender interferometers and simple ring resonators.
Describe the properties of surface plasmon polaritons (SPP). Set up the wave equation describing SPP, and outline the dispersion diagram for SPP waves at air/metal interfaces.
Describe prism- and grating-assisted coupling of light into SPP modes, and have knowledge of prism-assisted beam-splitting in the THz regime.
Describe waveguidance of broadband signals in the THz range,the properties of dispersion-free as well as dispersive metallic waveguides, and loss mechanisms for THz waves due to finite electrical conductance in waveguides.

Starting from Maxwell’s equations, the fundamental principles for localization and manipulation of light are established. Dielectric waveguides, their geometries and mutual coupling, will be discussed. Furthermore, plasmonic waveguides and metallic waveguides for THz radiation are introduced. The course gives an introduction to the building blocks of optical circuits, such as passive waveguides, Bragg gratings and couplers. Microstructured optical fibers and their bandgap effects are also introduced. The course contains excursions to danish companies, thus giving a good impression of the ongoing activities within the field.

10036/31400/34020/34021, Knowledge of Maxwells field equations, and the electromagnetic wave equation. Knowledge of vector mathematics, calculus, and differential equations.

Lectures with exercises.