Integrated Broadband Mode Division Demultiplexer in Waveguide Arrays

On-chip mode division (de)multiplexing plays a significant role in the integrated devices to greatly improve communication capacity. One of the pursuing goals of mode division (de)multiplexer is how to realize such devices with larger bandwidth and better fabrication tolerance. However, integrated broadband mode division (de)multiplexing devices were rarely 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 lithium niobate-on-insulator waveguide array. By taking advantage of the fact that different modes in the waveguide array have different group velocity, we experimentally confirmed 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 as well as quantum computing.