Abstract: Intrachannel Four-Wave Mixing (IFWM) is one of the most important nonlinear effects in optical fiber transmission systems with a bit rate higher than 10Gb/s. It induces the timing jitter to ‘1’ pulses and produces ‘ghost’ pulses to ‘0’ pulses, which will worsen the eyediagram and result in a bit error. In this paper, the mechanism of IFWM is analyzed in detail. And the abilities of return-to-zero (RZ), carrier-suppressed return-to-zero (CSRZ), and alternate mark inversion (AMI) to suppress the ‘ghost’ pulse induced by IFWM are theorectically compared. The results show that the AMI code is the most effective one in suppressing the ‘ghost’ pulse, CSRZ is the moderate one, and the RZ code is the poorest one. Numerical simulation is utilized to validate the conclusion. The conclusion is a good reference for designing of high speed optical fiber transmission systems.

Key words: optical fiber transmission system, intrachannel four-wave mixing, carrier-suppressed return-to-zero, alternate mark inversion, ‘ghost’ pulse