We demonstrate compact, low-loss ($<5\mathrm{dB}/\mathrm{cm}$) Parylene C photonic waveguides in a flexible, biocompatible, all-polymer platform suitable for implantable applications. The scattering loss due to the sidewall roughness resulting from the reactive ion etching of Parylene C was identified as the primary source of propagation loss. A fabrication process utilizing the conformal coating of Parylene C was developed to significantly reduce waveguide propagation loss (by more than 30 dB/cm). We also performed thermal annealing at 300°C to smoothen the sidewalls; however, it was found to adversely affect the waveguide performance.

中文翻译：

---

用于光学植入物的低损耗柔性聚对二甲苯光子波导

我们展示了紧凑，低损耗的（$<5\mathrm{D\; b}/\mathrm{厘米}$）柔性，生物相容性，全聚合物平台中的聚对二甲苯C光子波导，适用于可植入应用。归因于聚对二甲苯C的反应性离子蚀刻导致的侧壁粗糙度所引起的散射损耗被确定为传播损耗的主要来源。开发了利用聚对二甲苯C的保形涂层的制造工艺，以显着降低波导传播损耗（降低30 dB / cm以上）。我们还在300°C下进行了热退火，以使侧壁光滑。但是，发现对波导性能有不利影响。