Exploitability of Butt-Coupling between Single Mode/Multi Mode VCSEL and G.652 SSMF for future Green Radio-over-Fiber Infrastructures

Green and low-cost radio-over-fiber infrastructures for the capillary distribution of millimeter-wave signals can straightforwardly be developed through the use of low-consumption devices and the re-use of current deployed fibers. In particular, green infrastructures could be achieved by using Gallium-Arsenide Vertical Cavity Surface Emitting Lasers (VCSELs) operating around 850nm together with the standard G.652 fiber of 9-micron core diameter (SSMF) already installed inside building for providing internet connection via the Fiber-to-the-Home (FTTH) technology. In this context, the use of simple butt-coupling between VCSEL and SSMF is an attractive option in view of the targeted low-cost of the final system. However, all the commercial and currently available VCSELs are designed to be coupled with multimode fibers for short length datacom applications, and the coupling with SSMF is typically not optimized. In this work, we investigate the practicability of butt-coupling between high-performance multimode and singlemode VCSELs and SSMF, in view of 5G-and-beyond Radio over Fiber applications.