Performance Investigations of DFMA-PON Systems Using a Parallel IM/PM Transmitter for Dispersion Compensation

In the digital filter multiple access (DFMA) passive optical network (PON) systems based on direct detection (DD), due to the existence of fiber dispersion, the power fading phenomenon occurs when using a single photo detector (PD) to make optical signals transform into electrical signals, which affects the transmission capacities of the system. Therefore, so as to ensure the effective transmission capacities of the DFMA-PON system, this paper proposes a scheme that uses a parallel intensity modulation (IM)/phase modulation (PM) structure at the transmitter. According to the frequency responses of IM signal and PM signal are complementary in the same frequency range, we can use one way of modulation to compensate the other one which was damaged by dispersion. So the sub channels generated by the digital orthogonal filters in the DFMA-PON are allocated to the corresponding IM or PM modulation method. The numerical simulation results illustrate that the system transmission rate can reach 66.67Gb/s when bit error rate(BER) is lower than 3.8 × 10
⁻³
after a 25km standard single mode fiber(SSMF) transmission, it proves that the scheme proposed in this paper can effectively avoid the impact of power fading due to the chromatic dispersion on the system.