Opt Lett. 2018 Jun 15;43(12):2868-2871. doi: 10.1364/OL.43.002868.
We demonstrate broadband and low-loss three-mode and six-mode scramblers employing CO-laser inscribed long-period gratings (LPGs) for space-division multiplexing. Step-index (SI) few-mode fibers are used to avoid mode coupling to the cladding modes. We characterize the mode scramblers using a swept-wavelength interferometer. Mode-dependent loss (MDL) and modal transfer matrices over the C+L band are presented. Demonstrated LPGs with negligible MDL and low insertion loss contributed to high-performance CO-laser inscription. The total MDLs induced by the SI fiber with LPGs in three-mode and six-mode scramblers are measured to be 2 and 4 dB, respectively.
我们展示了使用 CO 激光写入的长周期光栅（LPG）实现的宽带、低损耗三模和六模解复用器。采用阶跃指数（SI）少模光纤来避免模式耦合到包层模式。我们使用扫频波长干涉仪对模式解复用器进行了表征。给出了 C+L 波段的模式相关损耗（MDL）和模态传输矩阵。具有可忽略的 MDL 和低插入损耗的 CO 激光写入 LPG 有助于实现高性能器件。三模和六模解复用器中 SI 光纤和 LPG 引起的总 MDL 分别测量为 2dB 和 4dB。
