Unlocking multidimensional optical multicasting based on multi-mode PIN silicon waveguides

Multidimensional optical multicasting can increase the number of multicast optical channels and enhance spectrum utilization, which is crucial for future high-capacity optical networks and high-performance optical computing. However, simultaneously multicasting more channels results in higher energy density, which increases nonlinear loss within the waveguide and hinders practical applications. In this study, we introduce a reverse-biased PIN junction in the multi-mode waveguide to reduce nonlinear loss. Leveraging the multi-mode PIN silicon waveguide, we experimentally demonstrate a multidimensional multicasting strategy to simultaneously multicast an 80 Gb/s QPSK signal across 14 channels in both modes and wavelengths. Due to the PIN waveguide, the output power of the converted light after four-wave mixing (FWM) in three modes, TE0, TE1, and TE2, can be increased by 13 dB, 11.7 dB, and 7.7 dB, respectively. Furthermore, the 80 Gb/s QPSK signal can be multicast in three modes and from one wavelength channel to nine, seven, and two wavelength channels, respectively. All channels demonstrate clear constellation diagrams and error-free performance ( bit error rate <3.8×10 −3 ). This demonstration provides a viable solution for multicasting in future mode and wavelength hybrid multiplexing optical networks, while also enhancing the capabilities of high-speed optical computing.