Dissertation Title: “Integrated electro-optic, microwave, and nonlinear photonic devices on thin-film lithium niobate”
Abstract:
Lithium niobate has numerous extraordinary features that make it a useful material for a wide range of applications, particularly in optics. The material's strong electro-optic effect and second-order nonlinearities are two prime examples with applications in optical modulation and wavelength conversion, respectively. The thin-film lithium niobate technology has revitalized the conventional optical applications of the material during the last decade. The thin-film platform is now one of the most actively investigated subdisciplines in integrated photonics. Optical waveguides on this innovative platform possess high index contrast, resulting in a size reduction of more than 20 times and a bending radius decrease of about two orders of magnitude when compared to traditional counterparts formed by diffusion or exchange of dopants.
These ultracompact waveguides facilitate the realization of highly efficient photonic devices, some of which are presented in this work. First, tunable dual-channel integrated Bragg filters with ultranarrow linewidths are demonstrated. These filters have potential applications in optical communication, sensing, and quantum optics. Next, high-speed Mach-Zehnder electro-optic modulators with an extrapolated 3-dB bandwidth of 170 GHz and low half-wave voltage-length product of 3.3 V.cm are presented. Furthermore, microwave-to-optical converters with integrated antennas and optical waveguides are demonstrated with improved efficiency compared to the currently existing devices for integrated microwave photonics applications. Afterward, fabricated periodically-poled lithium niobate devices are utilized to illustrate nonlinear wavelength translators through cascaded sum- and difference-frequency generations. Finally, further works on these research topics, which are appropriate for future research, are discussed.
Educational Career:
BS: 2014, Electrical Engineering, Sharif University of Technology
MS: 2017, Applied Physics, University of Tehran
Committee in Charge:
Sasan Fathpour, Chair
Peter Delfyett
Patrick LiKamWa
Arkadiy Lyakh, External
Approved for distribution by Sasan Fathpour, Committee Chair, on May 12th, 2022.
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