Ultra-compact multichannel optical waveguide crossings are designed by a particle swarm optimized inverse-design method. The 2 $\times$ 2 TE (TM) device has an ultra-small footprint of 2 $\times 2\mathrm{\mu }$m² and exhibits a high transmission efficiency of 69.1% (89.7%) and low crosstalk of −34.4 dB (−84.8 dB) at 1550 nm. The devices can work within a large range of pixel size and waveguide width, suggesting high process tolerance of the design method. To further extend the functionality, a 3 $\times$ 3 device with the same size is designed, which exhibits a remarkable transmission efficiency of 47.6%, 61.8%, 67.2%, and low crosstalk of −33.3 dB, −39.2 dB, and −49.9 dB, respectively, for the three transmission paths. In addition, by adjusting the structure, other types of 3 $\times$ 3 devices with different transmission paths are demonstrated. The ultra-compact broad-bandwidth high-process-tolerance optical waveguide crossings have great potential in high-integration photonic-integrated circuits.

超紧凑的多通道光波导交叉由粒子群优化逆设计方法设计。2$\times$ 2 TE (TM) 器件具有 2 的超小尺寸 $\times 2\mathrm{\mu }$m ²并且在1550 nm处表现出69.1% (89.7%)的高传输效率和-34.4 dB (-84.8 dB)的低串扰。这些器件可以在很大的像素尺寸和波导宽度范围内工作，表明设计方法的高工艺公差。为了进一步扩展功能，一个 3$\times$设计了相同尺寸的 3 器件，对于三个传输路径，其传输效率分别为 47.6%、61.8%、67.2%，以及-33.3 dB、-39.2 dB 和-49.9 dB 的低串扰。此外，通过调整结构，其他类型 3$\times$演示了具有不同传输路径的 3 种设备。超紧凑宽带高工艺公差光波导交叉在高集成光子集成电路中具有巨大潜力。