Orthogonal Frequency Division Multiplexing (OFDM) assumes a huge job in the modem media communications system. The range of wireless communication is limited, but this technology has many advantages over its counterparts. To cater to the advantages of OFDM a new concept known as optical OFDM came into realization. Using advantages of both optical communication and OFDM long-distance transmission is possible. This paper discusses the two variants of optical OFDM namely DC biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM) along with their basic advantages and mathematical description. The Peak to Average Power Ratio (PAPR) mitigation techniques are discussed and simulation results are presents under various schemes.