New Prospects of Optical Wireless Communication Systems Exploiting VCSEL-Based Transmitters

In the last decades, Vertical Cavity Surface Emitting Lasers (VCSELs) emerged as a dominant technology for short-reach high-data rate networks thanks to several advantageous features. These include low power consumption, high modulation speeds, low costs, and compact size. More recently, these inherent characteristics of the VCSELs have also made them exceptionally suited for a variety of Optical Wireless Communication (OWC) applications, particularly for short-distance links, up to a few meters. This paper reviews a range of new and promising applications for VCSELs within emerging OWC domains: Data Centers (DCs), space, and harsh environment. We present and discuss different VCSEL-based OWC systems that were designed, implemented, and tested in these emerging scenarios. For the DCs scenario, we present a novel approach to establish OWC links able to reach data rates up to $\text{40} \,{\text{Gbit}}/{\text{s}}$ with a single VCSEL. In the space environment, innovative OWC systems can support data communication among electronic elements placed in line-of-sight outside the spacecraft or inside a small satellite. VCSELs can be also exploited for data transmission in the very harsh environment of high-energy physics experiments. Here, a $\text{10} \,{\text{Gbit}}/{\text{s}}$ OWC system was designed for the Board-to-Board (B2B) link in High Energy Physics (HEP) experiments. Since space and HEP applications exhibit extreme conditions, the OWC systems and, particularly, the VCSELs were tested to assess their behavior under strong mechanical, thermal, and radiation stress.