Fibre optic-VLC versus laser-VLC: A review study

Abstract

The exponential increase in the demand for a fast and reliable wireless mobile network motivates the need for researchers to engage more actively in visible light communication (VLC) technology. This increase happens in parallel with the augmentation of the population to be accommodated. As a result, the radio frequency spectrum is overcrowded. VLCs, which are part of optical wireless communications, are unregulated ultra-wideband spectrums that offer an alternative to solve RF bandwidth exhaustion. The OWC has demonstrated, among others, a throughput of 100 Gbps and is capable of offloading large data traffic from RF networks. One of the VLC main backdrops is the distance for which light signals can be transmitted, which is generally short in nature. However, this is overcome by its combination with other technologies, such as fibre optics (FO) and laser technologies, to mention only a few, which form a cascaded system with VLC. The data offloaded is fed to the cascaded system of FO-VLC and laser-VLC. In this paper, we provide a comparative review of cascaded FO-VLC and laser-VLC systems. We survey the technology that can provide optimized communication and high bandwidth. The choice of cascaded system to be used or considered is dependent on the area of application. A comparison is conducted from the simulated results of both cascaded systems considering parameters such as the gain and throughput. The FO-VLC cascaded system shows that system gain always decreases as distance increases for a range of reflection coefficient, and slightly decreases with attenuation coefficient. The gain of the laser-VLC cascaded system decreases with an increase in transmission distance for a given range of floor and ceiling reflection coefficient and decreases slightly with attenuation intensity. From our investigation, it is clear that FO-VLC and laser-VLC are outstanding optical cascaded systems, which can be exploited in applications with a harsh environment. This research also highlights standardization efforts, advanced modulation schemes and coding techniques so far for VLC, FO and laser system and their promising applications.