Effect of Gordon-Haus jitter on nonlinear optical loop mirror (NOLM) demultiplexing

One of the major problems associated with high-speed optical time division multiplexed soliton transmission systems is the timing jitter error associated with individual soliton pulses. The two physical effects that cause soliton jitters are the amplified spontaneous emission (ASE) noise in in- line optical amplifiers and soliton interaction. While soliton interaction is negligible when the duty cycle of transmitted pulses is small enough, the root-mean-square (rms) soliton jitter due to culminated ASE noise is a fundamental factor that limits the bit-rate distance product in high-speed long-haul data transmission systems. Soliton jitter is detrimental to all-optical time division demultiplexing as it would manifest itself into a relative intensity noise in the data recovery process at the optical receiver. This paper investigates the possibility of minimizing the ASE-induced soliton jitter by changing the spacing between in-line optical amplifiers. It is found that the rms soliton jitter decreases with the amplifier spacing and the minimum soliton jitter can be attained in the case of distributed amplification. These results have significant implications to all-optical time division demultiplexing in the sense of taking into account the amplifier spacing in the process of optimizing system parameters to achieve minimum power penalty of the all-optical demultiplexer. The optical demultiplexer used in the analysis is a non-linear optical loop mirror.