斯托克斯域解偏振复用技术在相干光通信系统中应用

发布时间：2018-04-27 02:29

本文选题：斯托克斯域 + 解偏振复用　；参考：《电子科技大学》2014年硕士论文

【摘要】：相干光通信可以容忍光纤色散效应造成的的劣化和扩展光纤C波段的容量,同时也拥有很高的动态范围和灵敏度,这使得相干光通信成为下一代光通信系统的主导技术。偏振复用技术可以成倍地提高传输速率并且可以灵活地在电域进行均衡,所以偏振复用技术在今后的应用中将会越来越广泛。偏振复用系统中两个独立且相互正交的偏振态传输时会受到光纤中多种因素的影响,偏振态会随机旋转并且形成相互之间的串扰,导致接收端检测到的信号发生不同程度的混叠。所以,对于偏振复用系统来说,必须在接收端实现信号的解偏振复用。基于斯托克斯域的解偏振复用方法(SS-PDM),可以容忍色散(CD)和偏振相关损耗(PDL)。此方法是利用偏振复用信号在斯托克斯域分布的特点来找出一个逆矩阵来恢复出原始的偏振态。本文主要利用SS-PDM算法的优势和特性将其创新性地应用到相干光通信系统中:1.提出将SS-PDM应用于相干光PDM-OFDM系统,这样无需在发射端插入训练符号就能实现解偏振复用。此方法可以用于不同调制的子载波并且不需要训练符号,减小了系统开销。用66.6-Gb/s的子载波4QAM调制的相干光PDM-OFDM系统和133.3-Gb/s的子载波16QAM调制的相干光PDM-OFDM系统进行了实验验证,同时分析了这种方法的收敛速度,数十个符号就能达到收敛。2.提出一种基于SS-PDM的改进的恒模算法。其可以在一个较大的PDL范围内避免奇异值问题的产生,还可以提高收敛速度。用100 Gbit/s的PDM-QPSK系统,引入PDL去验证了这种改进的CMA。此外,还分析了改进的CMA的收敛速度的提升。最后,做了一个背靠背的实验来对改进的CMA进行了验证。3.提出一种基于斯托克斯域的PDL监测和补偿并将其应用于CO-OFDM系统,该方法通过偏振复用信号在斯托克斯域分布的特点计算出PDL并且通过旋转移动该分布实现PDL的补偿。然后用仿真进行了验证。对于CO-OFDM系统,用66.6-Gb/s的子载波4QAM调制的相干光PDM-OFDM系统和133.3-Gb/s的子载波16QAM调制的相干光PDM-OFDM的实验系统进行了验证。
[Abstract]:Coherent optical communication can tolerate the degradation of fiber dispersion effect and expand the C-band capacity of fiber, and it also has a high dynamic range and sensitivity, which makes coherent optical communication become the dominant technology in the next generation optical communication system. Polarization multiplexing technology can increase the transmission rate exponentially and equalize flexibly in the electric domain, so polarization multiplexing technology will be more and more widely used in the future. Two independent and orthogonal polarization states in polarization multiplexing systems are affected by a variety of factors in the optical fiber. The polarization states rotate randomly and form crosstalk between them. The signals detected at the receiving end are aliased to varying degrees. Therefore, for polarization multiplexing systems, depolarization multiplexing of signals must be realized at the receiving end. The depolarization multiplexing method based on Stokes domain can tolerate dispersion CDT and polarization dependent loss (PDL). Based on the distribution of polarization multiplexing signals in Stokes domain, an inverse matrix is found to restore the original polarization state. This paper mainly uses the advantage and characteristic of SS-PDM algorithm to creatively apply it to the coherent optical communication system. In this paper, SS-PDM is applied to coherent optical PDM-OFDM system, so that depolarization multiplexing can be realized without inserting training symbols into the transmitter. This method can be used for different modulation subcarriers and does not require training symbols, thus reducing system overhead. The coherent optical PDM-OFDM system modulated by 66.6-Gb/s subcarrier 4QAM and the coherent optical PDM-OFDM system modulated by 133.3-Gb/s subcarrier 16QAM are experimentally verified. The convergence rate of this method is analyzed, and the convergence rate of dozens of symbols is analyzed. An improved constant modulus algorithm based on SS-PDM is proposed. It can avoid singular value problems in a large range of PDL and improve the convergence speed. Using 100 Gbit/s PDM-QPSK system, PDL is introduced to verify the improved CMA. In addition, the improvement of the convergence rate of the improved CMA is analyzed. Finally, a back-to-back experiment is done to verify the improved CMA. 3. This paper presents a PDL monitoring and compensation based on Stokes domain and applies it to CO-OFDM system. The PDL is calculated by polarization multiplexing signal distribution in Stokes domain and the compensation of PDL is realized by rotating the distribution. Then it is verified by simulation. For CO-OFDM system, the experimental system of coherent optical PDM-OFDM modulated by 66.6-Gb/s subcarrier 4QAM and coherent optical PDM-OFDM modulated by 133.3-Gb/s subcarrier 16QAM is verified.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1

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