Based on this function, the low DPF at OSSB can be obtained if the system generates the carrier signal and \(+1\)st order sideband only. To produce this condition, the OSSB modulation must be operated at low \(m\leq 0.1\) because higher \(m\) will generate more sideband orders. A higher number of sideband orders will automatically increase the DPF. However, the OSSB is only effective at low \(m\leq 0.1\). However, to increase the efficiency of optic-electric conversions at the OSSB, a high \(m\) value is needed [22]. Therefore, it will be interesting to reduce the DPF value at high \(m=1\). In wireless communication, increasing the direct signal power [25] and using irregular phases can reduce the effect of fading. Then, the concept of suppressing fading in wireless communication can be applied to RoF communication to suppress the effect of DPF. As a novelty, this paper proposes an asymmetric carrier divider as a direct signal with an irregular RF phase on a DD-MZ modulator for eliminating DPF, as shown in Figure 1. In detail, the optical source generated using a laser diode (LD), \(E_{in}(t)\) is divided using an optical splitter (OS) with asymmetrical values such as power modulation (P\({}_{\text{DD-MZM}}\)) and carrier arm (CA) power (P\({}_{\text{CA}}\)). The signal at P\({}_{\text{DD-MZM}}\) is modulated using DD-MZM, and the modulated signal (\(E_{DD-MZM}(t)\)) is generated. The signal at the CA is added to \(E_{DD-MZM}(t)\) using an optical combiner (OC), which produces the transmitted signal (\(E_{TX}(t)\)). The \(E_{TX}(t)\) is transmittedusing fiber link \(H(f)\) and produces received signal (\(E_{RX}(t)\)). The \(E_{RX}(t)\) is detected and recovered using a photodetector (PD) and produces \(X_{rec}(t)\). This proposed method is called an asymmetric carrier divider system. Furthermore, to further reduce the DPF value that is caused by multi-sideband order, this paper also proposes the irregular RF phase. Therefore, the optimum \(E_{DD\text{-}MZM}(t)\) spectrum can be generated by adjusting the DD-MZM arm to produce a low DPF. The DPF level is determined using the deviation factor (DF). DF is the quantity of recovered RF signal power variation at the receiver that is measured over a certain range of fiber lengths. The smaller the DF is, the lower the DPF level or the smaller the effect of chromatic dispersion towards the RoF link. Therefore, we combine the asymmetric carrier divider system with the irregular RF phase on the DD-MZ modulator. Therefore, the combination of the optimum value of the power ratio and the optimum value of the irregular phase will reduce DF at RoF communication significantly. Furthermore, the significant contributions of this paper are as follows:  
1. The laser diode (LD) power (P\({}_{\text{IN}}\)) carrier is divided asymmetrically as the power modulation (P\({}_{\text{DD-}MZM}\)) and carrier arm power (P\({}_{\text{CA}}\)). The power P\({}_{\text{CA}}\) is used to compensate for the power of the carrier of the optical field of the DD-MZM output, which is reduced due to increasing \(m\). 2. The RF signal with an irregular phase (\(\theta\)) was applied to the DD-MZ modulator. Therefore, the optimum \(E_{DD\text{-}MZM}(t)\) spectrum can be generated by adjusting the DD-MZM arm. 3. The minimum DF is obtained when the P\({}_{\text{IN}}\) is separated as 75% for P\({}_{\text{CA}}\) and 25% for P\({}_{\text{DD-}MZM}\) with an irregular RF signal of \(\theta=48^{\circ}\) and bias point value of \(\gamma=3/4\). This proposed structure produces DF at \(m=0.1\) and \(m=1\) value are 0.008 and 0.03, or it reduced DF of 96.7% compared to OSSB. 4. The proposed system was successfully applied without additional power or filter, and the additional power or filter managed to increase the cost and complexity of RAP. Moreover, \(\theta\) is independent of fiber length. Our proposed model is applied for single fiber, not for routing scenarios with many nodes. 5. The proposed mathematical model of the system is developed based on the Bessel function.