Abstract

The exponential growth of network traffic, driven by applications such as IoT, 4K TVs, and cloud computing, demands an immediate need for enhancing network capacity. Optical fiber networks, fundamental to this enhancement, must handle massive data volumes efficiently. In order to address this, maximizing the existing optical network's capacity through dynamic networks and wavelength reconfigurability in wavelength division multiplexing (WDM) systems has emerged as a practical solution. Central to this approach are tunable optical filters (TOFs) and tunable lasers, which enable the selection and transmission of multiple data channels over a single fiber. In this work, a TOF with a 30 nm bandwidth (1535-1565 nm) across 5 channels, each with 30 nm tunability and 7.5 nm channel spacing, was selected to optimize performance within the C-band, known for its low attenuation and wide usage in optical communications. Silicon photonics, with its promise of smaller, faster, and more efficient photonic circuits, has advanced significantly, offering practical applications in integrated optical signal processors, external cavity lasers, and WDM systems. However, the mechanical tuning of photonic devices, crucial for dynamic network reconfigurability, requires robust actuators capable of delivering high force, broad travel range, and minimal footprint. This thesis investigates the design and optimization of MEMS actuators, specifically electrostatic comb drives with triangular finger configurations, to meet these stringent requirements. This research delves into various electrostatic actuator designs with a focus on optimizing force intensity, travel range, and spatial efficiency on Silicon-on-Insulator (SOI) platforms. It aims to enhance the performance of actuators for stiff, monolithic slab waveguides in silicon photonics, which requires high-force actuators due to their inherent mechanical rigidity. The study also explores the potential of angled electrode designs to improve microsystem actuator performance, providing a balanced approach to force intensity and travel range within a compact footprint. Additionally, the research addresses fabrication discrepancies and develops models to compensate for these variations, ensuring the reliability and consistency of manufactured devices. This thesis also covers the design and simulation of photonic components for a multichannel mechanically tunable optical filter and the external cavity of a diode laser. It involves the design of a concave diffraction grating (CDG) in Littrow mode, specifically tailored for compatibility with mechanical tuning. The study includes analytical modeling and validation through finite difference time domain (FDTD) and finite element method (FEM) with multiphysics simulations. The research further investigates the multichannel performance in various configurations and explores mechanical designs to reduce stiffness. Finally, the modeling and simulation of the designed multichannel optical filter are validated through experimental work, including selecting appropriate fabrication technology, performing scanning electron microscope (SEM) measurements, and testing the device using an edge-coupling setup. The fabrication of the optical filter configuration on Silicon-on-Insulator (SOI) platforms has been demonstrated, and the process has been considered in a way to facilitate easy post-processing for creating tunable optical filters. Overall, this thesis contributes to advancing silicon photonics by demonstrating that creating tunable filters on Silicon-on-Insulator (SOI) platforms is possible by providing innovative solutions for the mechanical tuning of photonic devices. These advancements, enhance the functionality, flexibility, and efficiency of optical communication systems.