Integrated Broadband Mode Division Demultiplexer in Waveguide Arrays

On-chip mode division (de)multiplexing plays a significant role in integrated devices to greatly improve communication capacity. One of the goals of mode division (de)multiplexing is to realize devices with larger bandwidth and better fabrication tolerance. However, integrated broadband mode division (de)multiplexing devices have rarely been reported up to now. In this work, we experimentally realize a broadband mode division demultiplexing device with a high degree of fabrication tolerance based on a lithium niobate-on-insulator waveguide array. By taking advantage of the fact that different modes in the waveguide array have different group velocities, we experimentally confirm that different modes in the waveguide array have different transverse displacements. The implementation of the integrated broadband mode division demultiplexer may have future applications in information processing technology, quantum communication, and quantum computing.