Bragg gratings in semiconductor waveguides

Inhaltsverzeichnis (Table of Contents)

• 1 INTRODUCTION
• 1.1 Introduction
• 1.2 Optical communication systems
• 1.3 Aims and objectives
• 1.3.1 Previous works
• 1.3.2 Work in this project
• 1.4 Structure of this thesis
• 2 THEORY
• 2.1 Chapter overview
• 2.2 Maxwell's equations
• 2.3 Boundary conditions
• 2.4 Reflection and refraction
• 2.5 Dispersion and loss
• 3 DIFFERENT TYPES OF BRAGG GRATINGS
• 3.1 Chapter overview
• 3.2 Principle of operation
• 3.2.1 Uniform gratings
• 3.2.2 Chirped gratings
• 3.2.3 Apodised grating
• 3.2.4 Phase-shifted gratings
• 3.2.5 Multiple gratings
• 3.3 Applications of Bragg gratings
• 3.3.1 Demultiplexer in WDM systems
• 3.3.2 Dispersion compensation
• 3.3.3 Applications in lasers
• 3.3.4 Applications in sensing technology
• 3.4 Fabrication of Bragg gratings
• 3.4.1 Fabrication of fibre Bragg gratings
• 3.4.2 Fabrication of semiconductor Bragg gratings
• 4 SIMULATION METHODS
• 4.1 Chapter overview
• 4.1.1 Introduction
• 4.1.2 Theory of the FEM
• 4.2 Least squares boundary residual (LSBR) method
• 4.2.1 Introduction
• 4.2.2 Theory
• 4.3 Transfer matrix method (TMM)
• 4.3.1 Introduction
• 4.3.2 Theory for uniform gratings
• 4.3.3 Theory for apodised gratings
• 4.4 Overlap integral (OI)
• 4.5 Coupled mode theory (CMT)
• 4.5.1 Introduction
• 4.5.2 Theory
• 5 SIMULATION RESULTS
• 5.1 Chapter overview
• 5.2 Examined structures
• 5.3 Results obtained from FEM
• 5.4 Analysis of the discontinuity junction using LSBR
• 5.5 Simulation of a complete grating using TMM
• 5.5.1 Introduction
• 5.5.2 Input data
• 5.5.3 Uniform gratings
• 5.6 Results obtained from the CMT
• 5.7 Simulation of fabrication inaccuracy
• 5.8 Apodised gratings
• 5.8.1 Different apodisation profiles
• 5.8.2 Simulation results
• 5.9 Chirped gratings
• 5.10 Phase-shifted gratings
• 5.11 Multiple gratings

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This thesis investigates the design, analysis, and fabrication of Bragg gratings in semiconductor waveguides. The work aims to develop a comprehensive understanding of Bragg gratings, explore various types and their applications, and evaluate different simulation methods for their design and analysis. The research focuses on advancing the knowledge and implementation of Bragg gratings in semiconductor waveguides for applications in optical communication systems.

• Theoretical understanding of Bragg gratings in semiconductor waveguides
• Exploration of different types of Bragg gratings (uniform, chirped, apodised, phase-shifted, multiple)
• Analysis of simulation methods for design and analysis of Bragg gratings (FEM, LSBR, TMM, CMT)
• Simulation and analysis of fabrication inaccuracies and their impact on grating performance
• Applications of Bragg gratings in optical communication systems (demultiplexing, dispersion compensation, lasers)

Zusammenfassung der Kapitel (Chapter Summaries)

The first chapter provides an introduction to optical communication systems, Bragg gratings, and the objectives of the thesis. Chapter 2 reviews the relevant theoretical concepts, including Maxwell's equations, boundary conditions, reflection, refraction, dispersion, and loss. Chapter 3 explores different types of Bragg gratings, their principles of operation, and various applications. The fourth chapter focuses on simulation methods, discussing the finite element method (FEM), the least squares boundary residual (LSBR) method, the transfer matrix method (TMM), and the coupled mode theory (CMT). Chapter 5 presents simulation results obtained using these methods, examining the performance of different Bragg grating designs. This chapter also analyzes fabrication inaccuracies and their effects on grating performance.

Schlüsselwörter (Keywords)

Bragg gratings, semiconductor waveguides, optical communication systems, demultiplexing, dispersion compensation, simulation methods, finite element method, LSBR, transfer matrix method, coupled mode theory, fabrication inaccuracy, apodised gratings, chirped gratings, phase-shifted gratings, multiple gratings.