High-density optical interconnects based on self-imaging in coupled waveguide arrays

Abstract

Rapidly increasing demand for higher data bandwidths has motivated exploration of new communication channels based on spatially multiplexed in-fibre and on-chip coupled light guides. However, the conventionally used periodically arranged coupled waveguides display complicated light propagation patterns, ranging from quasiperiodic to nearly chaotic. Taking a different approach, we spectrally engineer interwaveguide coupling to instigate self-imaging of the input light state at the array output and thus enable construction of novel high-fidelity interconnects. Simple implementation via modulation of the interwaveguide separations makes these interconnects realizable in all fabrication platforms. Their competitive advantages are negligible crosstalk-induced information loss, high density that exceeds the current standards by an order of magnitude, and compatibility with both classical and quantum information encoding schemes. Moreover, the wavelength-dependent self-imaging opens up new possibilities for wavelength and spatial division demultiplexing. The proposed analytical designs are supported by extensive numerical simulations of silicon-on-insulator, silicon nitride and silica glass waveguide arrays, and a statistical feasibility study.