基于绝热耦合器的硅基片上偏振-模式-波分混合复用器

To meet the needs of large capacity on-chip optical interconnection network, multi-dimensional hybrid multiplexing technology with large capacity and low loss has become a research hotspot of silicon photonics. At present, the main problem lies in crosstalk and fabrication tolerance, which limits the practical development of the multi- dimensional hybrid multiplexer. In order to reduce the crosstalk and improve the whole performance, it is necessary to study the mode coupling characteristics in detail. By analyzing the physical mechanism of mode coupling effect, we will focus on the influence of adiabatic mode evolution on crosstalk and light propagation characteristics, and develop the method to control the crosstalk. In this way, we can improve the channel number, operational wavelength range and fabrication tolerance of silicon hybrid demultiplexer by making full use of the unique properties of adiabatic couplers such as low crosstalk, wide operational wavelength, and large tolerance. Base on the work of silicon based adiabatic couplers and wavelength division multiplexer, this study will further study the problem of crosstalk and loss, and make clear the relationship between loss, mode evolution and coupling. By optimizing the structure parameters to reduce the crosstalk and loss as far as possible, the fabricated 128-channel silicon hybrid demultiplexer will enable polarization-, mode- and wavelength-division-multiplexing simultaneously with crosstalk <-30dB and insertion loss <5dB, promoting the development of large-capacity optical communication and optical interconnection link.

为了满足超大容量片上光互连网络需求，大容量、低损耗的混合复用技术成为硅光子学的研究热点。目前此类器件的串扰和带宽问题需要解决，限制了多维混合复用器件的实用化发展。为降低串扰、提升性能，必须深入研究与串扰问题相关的模式耦合特性。在全面分析模式耦合效应物理机制基础上，着重探索绝热模式演化对器件结构中串扰和光传播特性等方面影响，研究出控制串扰的方法，从而充分发挥绝热耦合器低串扰、宽工作波长、大工艺容差优势，达到提高硅基混合复用器件的通道数目和工作波长、降低器件串扰的目的。在我们已成功研制出硅基绝热耦合器和波分复用器的工作基础上，本研究将结合这两种器件，深入研究混合器件中的串扰和损耗问题，明确损耗与模式演化、耦合的关系，通过优化器件结构尽可能地降低串扰和损耗，使硅基偏振-模式-波分混合复用器件在<-30dB串扰、<5dB损耗下实现128通道的解复用功能，促进大容量光通信和光互连链路发展。

高容量光通信技术的发展，对混合复用技术提出了更高的要求。受限于串扰和带宽，混合复用技术需要进一步的研究。本项目开展了低串扰、宽操作波长范围的混合复用器件研究。首先，我们设计了一个高性能的偏振分束旋转器，串扰低至-40dB。另外我们研发了一个宽波长操作范围的光学梳状滤波器，采用的宽带多模干涉仪使得器件在无源情况下可以在140nm的频谱范围内实现优异的差分滤波功能。本项目设计了一种新型的偏振-波长解复用器，该器件对于工艺友好，并且极大提高了TE偏振的消光比。研究了绝热模式演化对器件结构中串扰和光传播特性等方面影响，总结出控制串扰的方法，设计的快速绝热结构的模式解复用器的串扰理论计算值低至40dB。我们希望这些器件能够促进大容量光通信和光互连链路发展。