On-Chip Non-Blocking Optical Mode Exchanger for Mode-Division Multiplexing Interconnection Networks

Optical mode exchange is an important technology for advanced mode-division multiplexing (MDM) interconnection networks, which provides enhanced flexibility by swapping signals between different mode channels. However, the available dual-mode exchange devices cannot fully meet the demands of MDM systems applying multiple orthogonal guided modes for parallel transmission. In this paper, an on-chip non-blocking mode exchanger is proposed based on a mesh network of interconnected Mach-Zehnder interferometers with demonstrated reconfigurability and scalability, and thus, the device is capable of swapping signals among arbitrary multiple optical modes at will. As a proof of concept, the non-blocking mode exchange among the first three order quasi-transverse electric modes is successfully demonstrated on a silicon-on-insulator platform. The device shows a large bandwidth covering the whole C band (1525–1565 nm), low insertion loss (less than 7.6 dB including the auxiliary mode coupling loss) and low inter-modal crosstalk (less than −14.3 dB) for all mode conversions. In order to demonstrate the data processing capabilities of this device, 40 Gbps data transmission experiment at the wavelength of 1550 nm is successfully carried out, and the obtained clear and wide-open eye diagrams indicate its good performance.