多模超信道全光波长转换硅基光子集成芯片关键技术研究

All-optical wavelength conversion (AOWC) is key technologies for next generation optic-fiber networks for offering network flexibility and potentially low cost operations. Traditional AOWC is designed for single mode operations. Recently, mode-division multiplexing (MDM) has been widely investigated as a promising way to overcome the capacity crunch of current single-mode fibers. Therefore, it is critical to develop upgraded AOWC schemes that could take care of MDM signals, i.e. MDM superchannels. In this project, we propose a novel scheme for MDM superchannels AOWC by converting signals from multimode to single mode and back afterwards and utilizing sophisticated single mode AOWC techniques in between. This scheme successfully solve the challenge of using a single nonlinear element for the AOWC of MDM superchannels. In addition, four wave mixing effect is adopted so that modal channels with scrambled information could also be wavelength converted. We propose to design and fabricate SOI-based photonic chip for the MDM superchannels AOWC. The integrated scheme offers great advantages over separated components since it provides much better uniformity of losses, conversion efficiencies as well as delays. More importantly, monolithic integration is possible since Si nanowaires can be used for both low loss interconnection as well as nonlinear applications. This scheme is also transparent for polarization and modulation format and scalable with mode number. We believe this work opens a promising way to perform all-optical signal processing for MDM superchannels.

全光波长转换是下一代光纤通信网络中的关键功能之一，能避免光电光转换，提高光网络灵活性。传统的波长转换是针对单模信号的。近年来，单模光纤的通信容量增长遇到非线性效应带来的根本危机，多模复用技术受到了广泛关注。因此，发展针对多模复用信号（多模超信道）的全光波长转换技术成为了亟待解决的问题。本项目创新提出将多模波长转换转化为若干单模波长转换，克服了基于多模器件的色散优化难题，特别是能对多模超信道特有的混叠信号进行波长转换，具有低损耗、偏振不敏感、调制格式透明、模式可扩展等重要优点。由于集成保证了方案所需的损耗、转换效率以及延时一致性，硅波导兼具低损耗和高非线性，因此本项目拟基于硅基微纳集成平台研究相关器件工作机理，研制硅基单片集成芯片。申请人在全光波长转换和多模复用器件方面有多年研究积累，拟从器件机理、转换机制、芯片制备、系统测试等方面开展研究，可望对我国高速大容量光网络的研究起一定的推动作用。

全光波长转换是下一代光纤通信网络中的关键功能之一，能避免光电光转换，提高光网络灵活性。传统的波长转换是针对单模信号的。近年来，单模光纤的通信容量增长遇到非线性效应带来的根本危机，多模复用技术受到了广泛关注。因此，发展针对多模复用信号（多模超信道）的全光波长转换技术成为了亟待解决的问题。本项目针对硅基光子集成平台开展了多模超信道全光波长转换的关键技术研究。在理论方面，基于多模非线性薛定谔耦合方程，建立了完整的数值仿真模型，验证了四波混频效应带来的多模式全光波长转换可行性，基于该模型研究了非线性交叉模式调制的线性化模型，并基于该模型开展了拓扑光子学的基础研究，研究了用于非线性转换效率提升的新结构，研究了基于狭缝波导填充非线性聚合物的四波混频效率提升，研究了基于pn结结构扫走载流子的四波混频效率提升。实验方面，研究了pn结硅基波导的载流子输运过程，经过理论分析，设计并制备了多模pn结波导，取得了片上四波混频效率的大幅提升。另外，还积极探索了不同的结构和材料平台，即硅基狭缝波导中填充具有高非线性参数的聚合物材料的片上集成器件，从理论和实验上验证了四波混频效率的有效提升。最终，通过寻找合适的集成波导参数，基于集成硅波导平台，制备了多模全光波长转换光子集成芯片并验证了基于模式内部四波混频效应的三路并行波长转换，以及三路40Gbit/s全光逻辑操作。