CAZAC-Clipping Technique for PAPR Reduction in Direct-Detection Optical OFDM System

High Peak-to-Average-Power Ratio (PAPR) is one of the major shortcomings of Optical Orthogonal Frequency Division Multiplexing (O-OFDM). In this paper, a novel PAPR reduction technique has been proposed which is the combination of the Constant Amplitude Zero Autocorrelation (CAZAC) sequence followed by clipping technique. It provides advantage over CAZAC matrix transform as clipping the CAZAC matrix processed signal reduces the probability of peak values, thus further minimizing the PAPR.  Simulation results show that implementation of proposed technique in direct detection optical OFDM (DDO-OFDM) system has reduced PAPR to a great extent. There is a slight change in BER performance while implementing the proposed technique compared to CAZAC matrix transform. However, by optimizing the clipping value, both PAPR and BER can be reduced significantly with low complexity and ease of implementation.