中国激光, 2009, 36 (4): 879, 网络出版: 2009-04-27
偏振相关损耗对偏振复用系统信道正交性的影响
Effect of the Polarization Dependent Loss on the Orthogonality of Channels in Polarization Division Multiplexing System
光纤光学 偏振相关损耗 光强衰减 偏振复用 fiber optics polarization dependent loss light intensity attenuation polarization division multiplexing
摘要
在偏振复用系统中,利用两个正交的偏振光作为不同的信道在同一根光纤传输,从而达到使传输信息量加倍的目的。在信号接收端,需要将这两个信道重新分离,分离时除了偏振模式色散(PMD)之外,还会受到偏振相关损耗(PDL)的影响。根据PDL的原理,推导了偏振复用系统中两正交信道夹角与PDL的数值关系,计算了PDL大小对系统的影响。并依据理论模型构建了实验系统,对光纤一个主轴光强进行衰减,描绘出信道间串扰和PDL之间的实验曲线,验证了理论分析的有效性。实验表明,PDL调至最小的时候,若要求串扰控制在-10 dB以内,差分群时延(DGD)应该压制在10 ps以内; 当DGD增大到140 ps以后,被标记和没被标记的信道信号强度达到了1∶1,系统则完全无法工作,在接收端无法分离信道。本项研究对于保证偏振复用系统的稳定性具有一定的指导意义。
Abstract
In the polarization division multiplexing system, the communication capacity can be doubled, depending on the transimission of two othogonal polarized beams as different channels in one optical fiber. These channels need to be seperated in the receiver end. Besides the polarization mode dispersion (PMD), polarization dependent loss (PDL) also affects the stability of system. On basis of the principles of PDL, the numerical relationship between the included angles of two orthogonal signal channels and PDL is derived for polarization division multiplexing system, and the effects of PDL to the system are also analyzed. According to the theorical model, the corresponding experimental structure is built to verify the theory through one axis attenuation in the optical fiber and the test curve description. The experiment shows that the crosstalk can be controlled below -10 dB when differential group delay (DGD) is less than 10 ps. Up to 140 ps, system cannot work any more with the same signal power of two channels. The research is useful to the stability of system.
王铁城, 姚晓天, 万木森, 刘铁根. 偏振相关损耗对偏振复用系统信道正交性的影响[J]. 中国激光, 2009, 36(4): 879. Wang Tiecheng, Yao Xiaotian, Wan Musen, Liu Tiegen. Effect of the Polarization Dependent Loss on the Orthogonality of Channels in Polarization Division Multiplexing System[J]. Chinese Journal of Lasers, 2009, 36(4): 879.