Integrated Photonic Functions Using Optically Anisotropic Materials

Integrated photonics is an emerging field within photonics research in which waveguides and optical components can be fabricated as an planar, integrated structure. In particular, silicon photonics based on dielectric nanowires have been established as a platform of choice for processing optical signals largely due to their near-lossless nature. One major constraint associated with dielectric waveguides is that their modes are diffraction limited. Plasmonic waveguides can compliment silicon photonics in a way that they can support modes that are not diffraction limited. Our group has successfully developed a plasmonic platform that can facilitate field-matter interaction, long-range propagation while exhibiting excellent coupling efficiency with silicon photonics. Nonetheless, dielectric and plasmonic waveguides still cannot fulfill the full suites of photonic functions. This is because optical modes supported in these structures are predefined by the design, and lack tunability over their modal properties. In this thesis, we will investigate the prospects of optically anisotropic materials/structures as new emerging integrated platforms for tailoring the modal attributes of the waveguide modes. These concepts have been abundant in the field of metamaterials for free space applications. However, thus far the advantage of anisotropic materials as an integrated platform has been largely overlooked, therefore the demonstrations of integrated devices using anisotropic 2D materials have been limited. In this thesis, we theoretically propose and demonstrate how to leverage material anisotropy of the optical materials/structures to tailor modal properties. First, a birefringent L-slot waveguide architecture will be introduced to serve as the basis for various polarization manipulating devices, allowing for the managements and control of polarization states of the lightwaves. Second, a metamaterial waveguide architecture that can effectively enhance the in-plane components of the modal field for graphene photonics will be presented. Third, the modal and dispersion behaviors of anisotropic 2D plasmonic waveguide will be explored. One striking advantage associated with this platform is that the material absorption inherent in this class of plasmonic material can play favorable roles in achieving intriguing integrated photonic functions, which can facilitate low-loss mode propagation, mode swapping, and diffractionless field canalization by regulating material absorption.

Department dc:contributor.department

Electrical and Computer Engineering

Year dc:date.issued

2022

Author dc:creator

• Chang, Po-Han

Advisor dc:contributor.advisor

• Helmy, Amr S

Handle dc:identifier.uri

http://hdl.handle.net/1807/110808

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/110808