模分复用系统中少模复用（解复用）技术研究

Research on Mode(de) Multiplexing Technology for Mode-Division Multiplexing System

近年来,在模分复用(MDM)光通信领域中采用少模光纤(FMFs)来增加传输容量的方法已经得到高度关注和深入研究,该方法可以突破单模光纤(SMFs)非线性香农极限.结合本课题组开展的模分复用方面的部分工作,比较系统、深入地分析讨论了模分复用研究过程中相对突出、经典的部分研究工作和最新进展,涉及少模模分复用器结构设计、特性及应用.分析讨论了一种基于相位板的三模式模分复用器、基于液晶空间光调制器(LCOS-based SLM)的模分复用器、常规标准型光纤光子灯笼、模式选择光纤光子灯笼、模式组选择光纤光子灯笼、模式组选择刻写波导型光子灯笼的结构设计、特性及应用.最后,给出了本课题组近期提出的新颖的定向耦合模分复用器以及模分复用器研究发展趋势,为模分复用光纤前传等系统应用提供有效支持.今后的较长一段时间,模分复用技术研究中的采用特殊材料和传输信道结构设计来实现低衰减、低串扰、高消光比、高模式选择性等指标仍然是通信领域需要继续探索的研究热点.

In recent years,mode-division multiplexing(MDM)using few-mode fibers(FMFs)has been intensively investigated as the method to increase transmission capacity.MDM can be beyond the nonlinearity Shannon limit of single-mode fibers(SMFs).Mode(de)multiplexers coupling to FMFs have drawn much attention in optical communications.Based on some of the works of our group on MDM,we systematically and thoroughly analyzes some classical research works and the latest progress on MDM,involving the mode(de)multiplexers design,characteristics and their wide applications.We firstly review and discuss some types of mode(de)multiplexers such as three mode mode-multiplexers with glass phase plates,mode-multiplexers with liquid crystal on silicon(LCOS)phase modulator,conventional standard fiber photonic lanterns,mode selective fiber photonic lanterns,mode group selective fiber photonic lanterns and mode group selective photonic lanterns with laser inscription waveguide.Then,we propose a novel mode(de)multiplexers with directional coupling.Finally,the developments trend of mode(de)multiplexers research are presented.It provides effective support for the application of MDM front-haul transmission system.Using special materials and fiber structure design to achieve low attenuation,low crosstalk,high extinction ratio,high mode selectivity in the study of mode(de)multiplexers is still our research focus for a long time.