High-density digital free-space photonic-switching fabrics using exciton absorption reflection-switch (EARS) arrays and microbeam optical interconnections

We describe a compact digital free-space photonic-switching module that uses microbeam optical interconnections based on stacked planar optics and exciton absorption reflection-switch (EARS) arrays. Microbeam optical interconnections become increasingly attractive as the number of optical input and output (I/O) ports increases because of their small size. The EARS device provides the digital-signal regeneration needed for constructing a multistage switching network. This paper mainly describes the experimental investigation of a prototype switch having a two-stage, 16-input, 16-output structure (four sets of 4×4 switches), with highly dense two-dimensional fiber array pigtails acting as high-density optical I/Os. The prototype is approximately 30×90×22 mm [60 cc]. A relay lens array inserted between stages eliminates the beam spreading caused by diffraction, which decreases the required positioning accuracy for the optomechanical packaging. Two-stage switching at a data transmission rate of 4 Mb/s has been demonstrated. Increasing the operating speed of the switch and introducing an easy assembly method to reduce assembly costs are future enhancements