Master Projects/Semester Projetcs

Optical Characterization of Periodically-Poled Thin-Film Lithium Niobate Waveguides


Thin-film lithium niobate is one of the most promising materials for a standardized PIC platform capable providing optimum conditions for a multitude of photonic processes. Conventionally, lithium niobate crystal has been a favourable due to its high electro-optic coefficient, high intrinsic nonlinearities, and wide transparency window. Devices based on lithium niobate have already showed superior performance on nonlinear frequency conversion via periodic poling compared to other materials platforms. With the recent advances on microfabrication, thin-film lithium niobate can now be directly etched to form low-loss waveguides and resonators. High index contrast between lithium niobate and the cladding enables the propagation of high intensity modes with strong confinement through the nonlinear medium, giving optimal conditions for efficient frequency conversion.

Project Description:

The project will focus on second-order nonlinearities within periodically-poled lithium niobate (PPLN), more specifically on second-harmonic generation and difference-frequency generation. We aim to optimize these fundamental building blocks to achieve broadband operation and/or high conversion efficiency. Tasks for this project can include(but not limited to) optical measurements on PPLN waveguides, characterizing the response at different pump/signal wavelengths & temperatures. In addition, the student will also be involved in the post-processing of these measurements for experimentally extracting waveguides intrinsic properties properties.

If you are interested, please contact Yesim Koyaz ([email protected]) for detailed information.



[1] Zhu, Di, et al., Advances in Optics and Photonics 13.2 (2021): 242-352.

[2] Rao, Ashutosh, et al., Optics express 27.18 (2019): 25920-25930.

[3] Ledezma, Luis, et al, Optica 9.3 (2022): 303-308.