LAUSR

Coherent Optical Orthogonal Frequency-Division Multiplexing (CO-OFDM) is widely used in optical communication systems, these systems suffer from many problems, including the high Peak-to-Average Power Ratio (PAPR). In this paper, a new method is proposed, it is based on Rotation Odd Constellation (ROC), this is done by dividing the subcarriers into two halves. The first half includes the Odd and the second consists of the Even subcarriers. A phase rotation is added to the first half, and no change is made in the second half. A simulation model has been accomplished by using Matlab platform and VPI transmission maker software to verify the efficiency of the proposed method and the improvment concerning Bit Error Rate (BER), Error Vector Magnitude (EVM) and Quality Factor (QF). The results have been collected for128 subcarriers, 4QAM, 16QAM and bit rate of 10Gb/s, shows the best performance is obtained when /4 rad is the rotation angle.