Investigation On The Influence Of Polarization Mode Dispersion In Optical Soliton Transmission And The Controlling Of Their Interaction

The current optical fiber communication system has become the main trunk of long-distance communication network. The optical fiber soliton is a special wave packet that can offset dispersion by principle of nonlinear self-phase modulation. Thus, it can keep the waveform unchanged in transmission process. Since there is polarization mode dispersion (PMD) in light pulses transmitting in optical fiber, the communication system of optical fiber can not meet the requirements of practical application gradually. In order to solve the side effects brought about by PMD, the research on PMD becomes more and more important extremely.In this paper, the single and multiple solitons'transmission properties are discussed in ideal case firstly. The effects are compared by means of increasing the initial separation distance of solitons, injecting unequal amplitudes and different phases. The unequal amplitude method is thought to be the best way of inhibiting the interaction of solitons. By choosing proper amplitude ratio, the soliton's pulse peak drift is greatly corrected, and the interaction between solitons is restrained. The study also shows that for multi-soliton transmission, the inhibitory effect of unequal amplitude method is weaker on odd number of solitons than on even number.Then symmetrical slit-step Fourier numerical method is used in this paper to solve the Nonlinear Schr?dinger equation and simulate the soliton transmission properties in the fibers. The inferences of the group velocity mismatch which denotes the magnitude of the birefringence on the soliton transmission are analyzed. The interactions of the optical solitons and transmission control techniques are also studied. It is shown that when the amplitudes of the two polarized components of a soliton transmitting in fibers presenting birefringence are unequal, the pulse peak of the soliton will drift on the time-axis and the drift extent rest with the magnitude of birefringence; the larger the birefringence is, the longer the drift will be. While when the amplitudes are equal, the solitons'pulse peaks don't drift on the time-axis but they can only keep their shape in transmission in case of the birefringence is small. If the birefringence of the fiber is randomly varying, the pulse peak drift aforementioned will be corrected. Whether the two polarized components of the soliton transmitting in fibers are equal or unequal, the intensity of the two component will change irregularly with the transmission distance but the composite intensity of the soliton pulses hardly varies as the two polarization component compensate each other.Finally, the paper studies the soliton interactions and transmission control technology and finds out the transmission distance of solitons, which are not affected by interaction will become shorter with the increase of group velocity mismatch in randomly varying birefringence fiber. Unequal amplitude method used in randomly birefringence fiber to inhibit the interaction of multiple solitons has a good effect. By choosing proper parameters and simulating, the soliton control technique such as synchronous modulation and non-linear gain control will make adjacent solitons not depart from the original time slots which are deviated from originally because of their intersection, and the both technique can get good control effects.