Here, a hybrid 6-mode × 6-wavelength division multiplexing transmitter based on lithium niobate-on-insulator (LNOI) is proposed as a groundbreaking solution for next-generation optical communication. This technique enables bidirectional communications over a. 516Tb/s MIMO-Free Mode/Wavelength Division Multiplexing Optical Wireless Communication System Chao Li, Xumeng Liu, Yunhong Liu, Peng Sun, Songyuan Hu, Zichen Liu, Zhixue He, and Shaohua Yu C.