We review the research progress of strictly nonblocking optical switches based on silicon photonics. We have developed a switch chip fabrication process based on a complementary metal-oxide-semiconductor pilot line and optical and electrical packaging technologies. We demonstrated all-paths transmission and switching of up to 32 input ports × 32 output ports with an average fiber-to-fiber insertion loss of 10.8 dB. Furthermore, we demonstrated an operating bandwidth wider than 100 nm for −30 dB crosstalk with double-Mach–Zehnder element switches in an 8 × 8 switch. For polarization-insensitive operation, we adopted a polarization diversity scheme and fabricated an 8 × 8 switch with fiber-based polarization-beam-splitters and two switch chips. The 8 × 8 switch exhibited a polarization-dependent loss of less than 0.5 dB. Moreover, an on-chip polarization diversity 8 × 8 switch integrated with polarization splitter rotators and two switch matrices on a single chip demonstrated a differential group delay less than 1 ps. Based on current technologies, we discuss the prospects for further port count expansion and remaining challenges for commercial deployment.

中文翻译：

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基于硅光子学的低损耗、低串扰、大规模光开关

综述了基于硅光子学的严格无阻塞光开关的研究进展。我们开发了一种基于互补金属氧化物半导体试验线和光电封装技术的开关芯片制造工艺。我们演示了多达 32 个输入端口 × 32 个输出端口的全路径传输和交换，平均光纤到光纤插入损耗为 10.8 dB。此外，我们在 8 × 8 开关中使用双马赫-曾德尔元件开关证明了 -30 dB 串扰的工作带宽大于 100 nm。对于偏振不敏感操作，我们采用了偏振分集方案并制造了一个带有基于光纤的偏振分束器和两个开关芯片的 8 × 8 开关。8 × 8 开关的极化相关损耗小于 0.5 dB。而且，在单个芯片上集成了偏振分离器旋转器和两个开关矩阵的片上偏振分集 8 × 8 开关表现出小于 1 ps 的差分群延迟。基于目前的技术，我们讨论了进一步扩展端口数量的前景和商业部署的剩余挑战。