面向弹性光网络的高性能光频梳研究

The superchannel transmission system based on optical multicarrier generator is of prime importance for the next-generation elastic optical network with high spectral-efficient, ultra-large capacity and flexible-grid. The optical frequency comb generator (OFCG) as a high-quality optical source, is one of the key components to implement the superchannel transmission system. Recently, the OFCG based on the recirculating frequency shifter (RFS) is an attractive one to generate high-quality optical multicarrier. However, the low carrier-to-noise-ratio (CNR), less carrier number and poor stability of dynamical tunability of the single laser based RFS-OFCG are the main disadvantages and should be solved so as to be applied to the next elastic optical network. The aims of this proposal are to analyze the noise property and built the model of noise suppression of the recirculating loop cavity, research the new scheme to broaden the bandwidth and design the dynamical equalization algorithm to achieve flexible tunability of the bandwidth and frequency-spacing of the proposed single laser based RFS-OFCG. Via the theoretical analysis, numerical simulation and experimental implementation, the relationship between the output CNR and the intra-cavity noise of the OFCG will be shown. Meanwhile, the output bandwidth can be further improved and the stability of the flexible tunability will be also achieved of the OFCG. Based on this research, the generation of high-quality combs with ultra-low noise, ultra-large bandwidth and flexible tunability would be achieved and are desired to meet the demands of the high-quality optical source of the multi-Tb/s superchannel transmission systems.

基于多个光载波构建超级通道传输系统对实现下一代频谱高效、超大容量及灵活栅格弹性光网络具有关键作用。光频梳作为一种高质量多载波光源系统是实现超级通道技术的关键器件；而基于循环频移的光频梳产生器是一种优选方案。本项目拟采用基本的理论分析和实验方法，针对基于单种子光源的循环频移光频梳的载波输出载噪比低、数目较少及动态可调稳定性不高等问题进行研究，分析其噪声调控机制、载波拓展原理及频梳输出稳定性与光电差异响应间的相互关系，建立超低噪声调控及超大带宽光频梳产生模型，设计光电差异响应动态均衡算法，并对其进行数值仿真和实验验证。通过本项目的研究，揭示循环频移内腔噪声对光频梳输出载噪比的影响规律，解决输出载噪比不高、输出数目偏少以及动态可调载波输出特性差异等关键问题，可望实现超低噪声、超大带宽与动态可调的高性能光频梳产生，满足超大容量尤其是百太比特级超级通道传输系统对发射端光源系统的高质量要求。

为了便于充分利用项目开展科研工作，在项目研究过程中，对项目研究计划内容做了一些调整。结合课题组前期研究优势，主要针对循环频移电光调制光频梳产生器、光频梳应用及模式复用光通信系统等方面做了一些与本项目研究内容相关的研究工作。具体研究工作主要体现在：① 提出了一种基于线性IQ调制器的光频梳产生机制；② 提出了一种基于双偏振IQ调制器的新型循环频移光频梳产生机制；③ 提出了一种基于偏振调制器的单边带频移器；④ 提出了一种基于光频梳和频谱干涉法的长距离少模光纤特性测量新方案；⑤ 提出并设计了基于矢量模复用和波分复用的光传输系统；⑥ 提出并设计了基于2个和4个矢量模式复用的自由空间光通信系统以及基于少模光纤的两模高速矢量光纤通信系统等。这些研究工作在完成项目研究内容的基础上，充分拓展了项目的研究内容范围，丰富了项目的研究内容，取得了很多有意义的研究成果。本项目在研究过程中，共发表标注项目资助科研学术论文22篇，其中SCI检索论文17篇，EI检索论文3篇，受邀撰写综述论文1篇；申请国家发明专利3项并获授权；同时，培养硕士毕业研究生4人。对比项目预期研究成果，本项目在执行时间里，已足额完成项目预期成果要求。