Two-stage digital free-space photonic switch using exciton absorption reflection switch (EARS) arrays

Digital free-space photonic switches that digitally regenerate optical signals at each stage are suitable for constructing a compact large-scale switching fabric. In a previous report, we demonstrated a single-stage, two-input, two-output, digital free-space photonic switch that uses an exciton absorption reflection switch (EARS). It provides optically controllable switching with optical signal regeneration. In this paper, we present the experimental results for a two-stage digital free-space photonic switch that uses cascaded EARS arrays and relay lens optics. The relay lens optics provides the low loss coupling between EARS arrays necessary for high-speed switching