VCSEL and LED Based Visible Light Communication System by Applying Decode-and-Forward Relay Transmission

In this investigation, we propose and demonstrate an integrated vertical-cavity surface-emitting laser (VCSEL) and blue light emitting diode (LED) based visible light communication (VLC) system by using the decode-and-forward (DF) relay scheme indoors. The 682 nm visible VCSEL can reach 3 Gbit/s on-off keying (OOK) modulation rate for 4 m free space transmission by applying 1.25 GHz bandwidth PIN photodiode (PD). Then, the VLC
_VCSEL
signal connects to multiple blue LEDs for broadcasting VLC
_LED
traffic in parallel. Therefore, the maximum VLC
_LED
rates of 775, 700, and 600 Mbit/s are obtained at the free space transmission lengths of 2, 3, and 4 m, respectively within the forward error correction (FEC) target under 4 m VLC transmission at the low detected power of 15 μW. In addition, the number of LEDs used in the DF relay VLC system depends on the practical requirement of VLC
_LED
rate and traffic length indoors.