Modeling and analysis of penalty on optical signal performance due to low-frequency subcarriers multiplexing

Using a conventional optical receiver model, we analyzed the penalties on the optical signal performance due to low-frequency subcarriers with a new approach, regarding the subcarrier as a sinusoidal distributed random variable of which the standard deviation is applied in the formula derivation. Then, the Q factor is derived as a simple analytic function of modulation index, OSNR, and the number of subcarriers. By using numerical analysis, our method agrees well with the proved theory and is more efficient and convenient for calculation.