Optical wireless communication (OWC) in the infrared and visible range is quite attractive solution, especially where radio communication face challenges. Visible light communication (VLC) a data communications medium uses visible light (VL) over a range of 400 and 800 THz (780–375 nm) and is a subset of OWC technologies. With an increasing demand for use of wireless communications, wireless access via Wi-Fi is facing many challenges especially in terms of capacity, availability, efficiency and security. Li-Fi uses intensity modulation and direct detection. Therefore, the signals must be strictly real valued and positive. These constraints pose limitation on digital modulation techniques. These limitations result in spectrum-efficiency or power-efficiency losses. In this paper, we investigate an amplitude shift keying (ASK) based orthogonal frequency division multiplexing (OFDM) signal transmission scheme for VLC technology. The ASK technique also works efficiently for transmission of digital data over optical fiber. In this paper, M ary ASK is proposed for use in OFDM systems.