| For optical fiber communication, high-speed long-haul transmission is always the goal to pursue. But the effects of fiber loss, dispersion and nonlinearity are the main obstacles. The appearance of optical amplifiers, especially the erbium-doped fiber amplifier (EDFA), has overcome the effect of fiber loss. Then the dispersion management (dispersion compensation) and the suppression of nonlinear effects have become hot research topics in the area of high-speed optical fiber communication. Recently, a fascinating phenomenon of pulse transmission, called optical soliton which occurring in the anomalous dispersion fiber through interaction between fiber dispersion and nonlinear effect,has been found by research. The appearance of soliton theory and the application of soliton transmission make it possible to realize super high-speed and super long-haul transmission. At present, both linear high-speed optical fiber communication system and soliton transmission system are mostly using EDFA as in-line amplifier. However, there is amplified spontaneous emission (ASE) noise in EDFA. The ASE noise accumulation of cascaded EDFA's will result in both Signal-to-Noise inferior in linear high-speed optical fiber communication system and so-called Gordon-Haus jitter and soliton interaction in soliton transmission system, thus restrict system transmission rate and distance. Phase sensitive amplifier (PSA) based on the principle of degenerate parametric amplification is a new optical amplifier. Comparing with EDFA,PSA has some advantages, such as low noise figure and effect of dispersion compensation. Applying PSA as in-line amplifier in linear high-speed optical fiber communication can prevent pulse from getting broader. And in soliton system, using PSA as in-line amplifier can not only overcome the Gordon-Haus restriction but also suppress the soliton interaction,thus the soliton stable transmission distance can be extended significantly. In this dissertation, we focus on researching the performance of both linear high-speed optical fiber communication and soliton transmission system using PSA as in-line amplifier. The performance was demonstrated through numerically solving the simplifying basic transmission equation and the generalized nonlinear Schrο&& dinger equation (NLSE) by means of the split-step Fourier method,that is the computer simulation. At first,this dissertation was focused on the research on the transmission performance of PSA in linear high-speed optical fiber communication. The simulation result shows that PSA is not suitable for single mode fiber (SMF) transmission systems because of high dispersion of SMF and limited effect of dispersion compensation by PSA. But if dispersion compensation fiber (DCF) is added to this system, signal speed and no-relay transmission distance can be largely improved by using PSA instead of EDFA as in-line amplifier. To non-zero dispersion shift fiber (NZDSF) links, PSA behaves a good effect of dispersion compensation, but the system performance is related to the signal speed and the spacing of PSA's. PSA can compensate negative dispersion as well as passive dispersion. When average signal output power from PSA is limited in a certain range, the system performance is rarely affected by signal output power. In passive dispersion, there is an optimum average signal output power of amplifiers, because the chirp caused by self-phase modulation (SPM) counteracts to that by group-velocity dispersion (GVD). If the phase shifting between pumping light and signal light in PSA is controlled in a certain level, the system performance can be free from its effect. Signal pulse shape can also work on the performance of PSA's system. Super-Guass pulse is preferred to Guass pulse. Secondly, the transmission performance of soliton system using PSA as in-line amplifier has been analyzed by computer simulation. For comparison, we also simulated the performance of EDFA's system. Three kinds of soliton transmission regimes are simulated. The simulation results show that without added any sol...
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