Study of Waveguide-Coupled Er-Doped Microdisk Resonators on LiNbO3

• Main Authors: Ying-Che Lin, 林穎哲
• Other Authors: 王子建
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/bmn6w8

碩士 === 國立臺北科技大學 === 光電工程系研究所 === 104 === LiNbO3 is a ferroelectric crystal features acousto-optic, electro-optic, and nonlinear optical properties. It does not have the light-emitting ability but can achieve optical gain by doping and pump source. When pumping erbium-doped LiNbO3, it produces optical gain. The LiNbO3 microdisk is fabricated by using ion implantation and chemical etching. A thin layer of erbium film is deposited on the LiNbO3, followed by thermal diffusion. Then the ion implantation causes lattice damage in certain depth of LiNbO3 substrate. After the implantation, the substrate is immersed in diluted HF which forms the undercut suspended waveguide coupled microdisk structure with high refractive ratio after the substrate is completely etched. The titanium diffused waveguide couples the microdisk in order to guide the light from microdisk to the edge of the substrate for measurement and analyzation. In this work, the transmission spectrum is measured by the means of tapered fiber coupling and we calculate the quality factor (Q-factor) of the resonator out of it. The maximum intrinsic quality factors of the 40μm, 80μm, 120μm and 160μm diameter undoped spiral disks are 4.954×103, 4.725×103,4.39×103 and 4.541×103. For the the corresponding diameter of erbium doped microdisk devices, the maximum intrinsic quality factors are 1.703×103,3.101×103,1.095×103 and 4.541×103. The intrinsic quality factors drop after the device is erbium doped. Moreover, we had noticed that in the same diameter, spiral disks have smaller free spectral ranges (FSR) than the microdisks have.