| dc.description.abstract | Silicon photonics has emerged as a pivotal technology within the realm of photonic
integrated circuits (PICs). This groundbreaking technology holds the potential to
overcome existing bandwidth bottlenecks in long distance communication through the
deployment of compact, integrated devices. The escalating demand for high speed data
transmission has precipitated the widespread adoption of dense wavelength division
multiplexing (DWDM) systems across optical networks. Among va rious material
options, silicon nitride stands out in the fabrication of coupled resonator optical
waveguides due to its inherent advantages: low propagation loss, distortion free
transmission, ample bandwidth, and compact form factor. These characteristic s make
silicon nitride waveguides well suited for applications in filter design, optical
modulators, and optical network infrastructure.
In this thesis, the author opts for the low-loss material, silicon nitride, to investigate the optimization of filter bandwidth based on coupled resonator optical waveguides (CROW). Initially, the thesis delves into the typical transmission response of add-drop ring resonators and double-ring resonators, leveraging OptSim Circuit and MATLAB for numerical calculations. Simulation results indicate that the bandwidth of the double-ring resonator can be enhanced, showing up to a 28% improvement compared to that of the conventional single-ring resonator. Subsequently, for the design of efficient filtering elements, the author examines double-ring resonators with varying design parameters. The findings reveal that asymmetric ring resonators possess a narrower half-width bandwidth and a significantly larger free spectral range, attributable to the Vernier effect.
Third,in this par t of the discussion, we further explore the design elements of coupled resonator optical waveguides by examining two designs of asymmetric coupled
resonator waveguides. Simulations reveal that these two asymmetric designs offer bandwidths up to 45 % greater than that of their symmetric counterparts.
Moreover, we delve into the relationship between the power coupling coefficient and the resulting bandwidth. A linear correlation emerges from our simulations,suggesting that enhancing waveguide coupling strength can lead to a significant increase in the bandwidth of the coupled resonator optical waveguides. This finding underlines the potential of optimizing waveguide coupling for the efficient enhancement of bandwidth in such systems
Furthermore, attention must be paid to the ripple effect in bandpass filters. This undesired phenomenon can be substantially reduced through careful optimization of the coupling coefficient. On the other hand, the inherent loss that optical waveguides exhibit is an influential facto r in the design process of coupled resonator waveguides.Precise adjustment of the waveguide loss parameters offers a method to not only mitigate the ripple but also facilitate the creation of an optimal bandpass filter. A notable observation from our stud y is the inverse proportionality between loss and bandwidth.This relationship presents an additional mechanism for achieving performance optimization in the design of coupled resonator waveguides
In summary, our proposed strategies for the optimization of
coupled resonator optical waveguides mark a significant step forward in the field. These methodologies present a powerful toolkit for boosting the bandwidth of bandpass filters based on Coupled Resonator Optical Waveguides (CROW). By refining the coupling coefficient and mitigating inherent waveguide loss through precise adjustments, we can notably enhance bandwidth and suppress the undesirable ripple effect.Our research also underscores the importance of understanding the inverse proportionality between loss and bandwidth, a relationship that adds another dimension to our optimization process.Looking forward, these advancements open up new avenues for improving the efficiency and functionality of optical communication systems, with potential implications for a broad array of applications in telecommunications and beyond | en_US |