Demonstration of an As<sub>2</sub>S<sub>3 </sub>Grating Coupler on Thin Film LiNbO<sub>3</sub>

• 作者: Chen Zhang Christi K. Madsen
• 来源期刊: 光学与光子学期刊(英文)
• 学科: 工学
• 关键词: Thin Film Lithium NIOBATE Arsenic Trisulfide Waveguide GRATING COUPLER GRATING Cavity
• 年，卷（期）: 2018,（4）
• 页码范围: 111-121
• 页数: 11页
• 分类号: TN2

摘要

We present both design and experimental results for an As2S3 grating coupler on a thin film LiNbO3 substrate. A basic grating coupler structure is designed with coupling efficiency of 53% to a single mode fiber. A maximum simulated coupling efficiency of 78.8% is achieved, assuming a polymer bonding process. The basic structure was fabricated, and the coupling efficiency was measured to be at least 23.4% at 1540 nm. Some of the loss may be attributable to non-grating sources, such as waveguide tapers and testing fiber tails. A grating cavity was then measured using the grating couplers. The cavity waveguide propagation loss was 2.0 dB/cm. For a 400 nm thick As2S3 on 500 nm thin film LiNbO3 on insulator, the confinement factor in the LiNbO3 crystal is 82.3% when the As2S3 waveguide width is 400 nm, showing that As2S3-on-thin film LiNbO3 is an excellent candidate for thin film electro-optic applications.