Duobinary modulation/predistortion techniques effects on high bit rate radio over fiber systems

<span>The work has presented duobinary modulation and predistortion techniques for the radio over fiber system enhancement achieving security level. Duobinary technique more compact modulated spectral linewidth with standard non return to zero code. Different NRZ/RZ rectangle shape employed that are namely exponential (ERS), Gaussian (GRS) different transmission bit rates. Switching bias voltage, switching RF voltage based LiNbO<sub>3</sub> modulator changed measure performance parameters of (RoF) system. Predistortion improves linearity transmitter amplifiers it is considered as a power efficiency technique. The optimum values Q-factor, data error rate (BER), electrical power, signal gain, noise figure, light signal/noise ratio achieved 8 Volt both biases/switching at 100 GHz. Signal quality/BER after receiver by using this frequencies. </span>