Demonstration of Compact Free-Space Optical MIMO Transmitter and Receiver Using Tri-Wavelength VCSELs and Silicon APDs

The use of multi-wavelength optical tests can be found in many applications including industrial manufacturing, food testing, and hospitals. This effort was targeted at making compact devices that could emit multiple wavelengths and detect multiple wavelengths simultaneously. Multiple approaches were considered. The chosen design accomplishes multiple input and multiple output spectral measurements through a direct-sequence spread spectrum (DSSS) technique. The devices demonstrated within this paper are novel in that they allow simultaneous operation of multiple wavelengths and multiple detectors using readily available components in a compact arrangement.