【作者】 李跃辉；

【导师】 许宗泽；

【作者基本信息】 南京航空航天大学 ， 通信与信息系统， 2005， 博士

【摘要】 超高速、超长中继距离传输一直是光纤通信所追求的目标。而光纤损耗、色散和非线性效应是其发展的主要限制因素。光放大器,尤其是掺铒光纤放大器(EDFA)的出现和实用化,克服了光纤损耗对传输距离的限制,因此色散管理(色散补偿)和非线性效应的抑制成为近年来高速光传输领域的研究热点。理论研究发现,光孤子是光纤色散和非线性效应互作用的产物。利用光孤子可以实现无脉冲畸变的光传输,从而使光纤通信向超高速、超长中继距离传输方向发展有了可能。 目前线性高速光纤通信系统和光孤子传输系统大多采用 EDFA 作为在线放大器来补偿光纤损耗导致的能量损失。由于 EDFA 存在放大的自发辐射(ASE)噪声,级联 EDFA 的 ASE 噪声积累,在线性高速光纤通信系统中将严重劣化系统的信噪比,缩短了系统的传输距离;在光孤子系统中引起孤子到达接收端的定时抖动(称为 Gordon-Haus 限制),同时还导致孤子互作用,由此也限制了孤子系统的传输速率和传输距离。 基于简并光参量放大原理的相敏光纤参量放大器(PSA)是新近出现的一种光放大技术。相对于 EDFA 而言,PSA 具有低噪声指数和色散补偿等优点。应用在线性高速光纤通信系统中,PSA 增益的相位敏感性对脉冲波形具有一定的整形作用,能够抑制光脉冲的展宽;应用在孤子通信系统中,PSA 可以克服Gordon-Haus 限制及抑制孤子间的互作用,从而显著延长孤子的稳定传输距离。 本论文提出把 PSA 作为在线放大器应用于线性高速光纤通信系统和光孤子系统。论文的中心内容就是采用数值求解简化的基本传输方程和非线性薛定谔方程,来研究在线放大器为 PSA 的线性高速光纤通信系统和光孤子系统的传输性能受系统和放大器参量的影响。 论文首先仿真研究了 PSA 应用于线性高速光纤通信系统的传输性能。研究表明:对级联 PSA 常规单模光纤(SMF)传输系统,由于 SMF 光纤的色散系数过大,PSA 自身色散补偿较弱而效果较差,PSA 不适合单独应用于此系统。而当附加色散补偿光纤(DCF)时,则信号速率和无中继传输长距离极大提高。对非零色散位移光纤(NZDSF)传输系统,PSA 具有良好的色散补偿效果,但系统的性能与传输速率和放大器间距有关;同时,PSA 对光纤的正、负色散同样具有良好的补偿效果;放大器平均输出信号功率限定在一定范围内,系统的性能更多还原

【Abstract】 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更多还原