Reconfigurable optical add-drop multiplexer (ROADM) is one of the key building blocks for on-chip optical networks, which can download the desired signals from the bus waveguide to the corresponding drop port and upload the local signals from the add port to the bus waveguide to achieve the signals dropping/adding between the local and the bus waveguide. In this letter, we propose a ROADM based on a Benes network for mode-division multiplexing systems. As a proof of the concept, a ROADM with three quasi-transverse electric modes (TE0-TE2) is fabricated and experimentally demonstrated, which can download signals from TEi (i = 0, 1, 2) mode channel in the bus waveguide to an arbitrary local drop port or upload local signals to TEi mode channel via an arbitrary add port. The excess loss of the fabricated device is less than 10.7 dB, and the crosstalk among different space or mode channels is lower than −13.7 dB. Finally, a 12 Gbps data transmission experiment is carried out to verify the performance of the device. The proposed device is reconfigurable and scalable, and thus, it is expected to be used for optical data processing in the mode-division multiplexing systems.

中文翻译：

---

一种用于模分复用系统的灵活且可重新配置的光分插复用器

可重构光分插复用器 (ROADM) 是片上光网络的关键构建块之一，它可以将所需信号从总线波导下载到相应的分路端口，并将本地信号从分插端口上传到总线波导以实现本地和总线波导之间的信号分/插。在这封信中，我们为模分复用系统提出了基于 Benes 网络的 ROADM。作为该概念的证明，制造并实验证明了具有三个准横向电模式 (TE0-TE2) 的 ROADM，它可以将信号从总线波导中的 TEi (i = 0, 1, 2) 模式通道下载到一个任意本地丢弃端口或通过任意添加端口将本地信号上传到 TEi 模式通道。制造的器件的超额损耗小于 10.7 dB，不同空间或模式通道之间的串扰低于-13.7 dB。最后进行了12 Gbps的数据传输实验来验证设备的性能。所提出的设备是可重构和可扩展的，因此有望用于模分复用系统中的光学数据处理。