Nedeljkovic Milos, Penades Jordi Soler, Mittal Vinita, Murugan Ganapathy Senthil, Khokhar Ali Z, Littlejohns Callum, Carpenter Lewis G, Gawith Corin B E, Wilkinson James S, Mashanovich Goran Z
Opt Express. 2017 Oct 30;25(22):27431-27441. doi: 10.1364/OE.25.027431.
We report transmission measurements of germanium on silicon waveguides in the 7.5-8.5 μm wavelength range, with a minimum propagation loss of 2.5 dB/cm at 7.575 μm. However, we find an unexpected strongly increasing loss at higher wavelengths, potential causes of which we discuss in detail. We also demonstrate the first germanium on silicon multimode interferometers operating in this range, as well as grating couplers optimized for measurement using a long wavelength infrared camera. Finally, we use an implementation of the "cut-back" method for loss measurements that allows simultaneous transmission measurement through multiple waveguides of different lengths, and we use dicing in the ductile regime for fast and reproducible high quality optical waveguide end-facet preparation.
我们报告了在7.5 - 8.5μm波长范围内锗硅波导的传输测量结果，在7.575μm处的最小传播损耗为2.5dB/cm。然而，我们发现在更高波长处损耗意外地大幅增加，我们将详细讨论其潜在原因。我们还展示了在此范围内工作的首个锗硅多模干涉仪，以及使用长波长红外相机进行测量优化的光栅耦合器。最后，我们采用“截断”方法进行损耗测量，该方法允许同时通过多个不同长度的波导进行传输测量，并且我们在韧性状态下进行切割以实现快速且可重复的高质量光波导端面制备。
