2023/07/10 by Mihnea Sandu, Alicia Petronela Rambu, Sandu, Mihnea Raoul +5
Engineering · #Advanced Fiber Optic Sensors #Applied Physics (physics.app-ph) #FOS: Physical sciences #Optics (physics.optics) #Photonic and Optical Devices #Semiconductor Lasers and Optical Devices
paper · pdf · doi:10.48550/arxiv.2307.05572
openalex publication_date 2023/07/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The actual techniques allowing the fabrication of waveguides in lithium niobate are not able to satisfy one of the demands of modern integrated photonics namely well-controlled tunability of index contrast over a large range of values from high-index contrast to low index contrast. This paper presents a simple and reliable method allowing well-controlled index contrast tunability while benefiting from optical nonlinearity of LiNbO3 waveguides fabricated using HiVac-VPE technique. The study involves LiNbO3 planar waveguides subjected to an annealing process for 1 to 5.5 hours. The waveguides are characterized before and after the thermal treatment, in order to determine the index contrast and to analyze the changes of index profile shapes. Furthermore, it is found that the index profile after annealing is fitted by an exponential function different from Gaussian fit found in APE technique. Additionally, index contrast dependence of the annealing time is also fitted by an exponential function. Our findings allow for well-controlled index contrast tunability, between high-index contrast (Δne=0.1) and low-index contrast (Δne=0.035), of LiNbO3 waveguides offering the opportunity for customization and enhancement of non-linear optical devices and photonics applications.