The increasing demand for bandwidth through modern applications and multimedia services has led to high-speed wireless communications. Optical Wireless Communications (OWC) encourages solutions that provide a higher data rate due to the large bandwidth available. In this paper, performance enhancement approaches will be studied and simulated for Visible Light Communication (VLC) as a case study. The Orthogonal Frequency Division Multiplexing (OFDM) systems are used to investigate Intensity Modulation/ Direct Detection (IM/DD) to improve the performance of VLC. The IM/DD in OWC requires positive real OFDM symbols, so there are many approaches to satisfy this requirement. This paper proposed a model of Asymmetrically Clipped DC-Biased Optical (ADO-OFDM) to use in OWC/VLC environment. The Proposed system has avoided the use of the noise cancelation technique that is used in traditional ADO-OFDM. The results show that the ADO-OFDM has the best spectral efficiency than DC-biased Optical (DCO-OFDM) and Asymmetrically Clipped Optical (ACO-OFDM). Also, it has better optical efficiency than DCO-OFDM with the equally overall Bit Error Rate (BER) at the same signal-to-noise ratio. Hamming channel coding/decoding with different code lengths is applied in various optical OFDM schemes for BER improvements. Furthermore, we simulate and analyze these optical OFDM systems with many modulation orders.