硅基光波导集成器件偏振模式调控机理及其应用研究

High speed silicon photonic integrated circuits have recently attracted the great attention, due to their advantages in many potential applications such as optical information processors, optical communication systems and optical sensing networks. So far, these silicon photonic components are polarization dependent in insertion loss and propagation constant, therefore hard to efficiently control polarization modes propagating in photonics. In consideration of polarization insensitive operation, the principles of low cost tunable polarization modes are required for polarization transparency of silicon photonics. In this work, physics of polarization modes in silicon photonics are firstly analyzed, focused on their effects on electro-optic interaction, also the tuning efficiencies of polarization modes are included for a novel operation and compensation method. On these basis, efficiently tunable polarization modes improve the total transmission data rate of silicon photonics and provide an option of low power consumption to split or convert polarization modes in these photonics. In recent years, our research team has successfully developed 10 GHz silicon optical modulators and sub-ns optical switches, which will help us in achieving polarization independent electro-optic devices in silicon, by introducing novel operation mechanisms and geometric configurations, as well as efficient tunability of polarization modes when operating these novel devices using advanced fabrication processes. Finally, the novel silicon photonic components can control their polarization mode difference as possible device designs of high speed photonic integrated circuits in silicon, which would give a powerful solution to many applications of silicon photonic integrated chips.

为适应光信息处理芯片、光通信系统和光学传感网络等应用需求，高速率硅基光波导集成器件已成为半导体光子学的研究热点。目前此类器件偏振相关损耗显著，模式控制效率低，限制了这些器件的实用化发展。为降低集成器件的偏振相关性和实现对其灵活控制，必须深入研究其偏振模式的调控机理。在全面分析偏振模式的物理机制和相关效应的基础上，着重探索偏振模式及其调控效率对器件电光效应等方面的影响，研究出对偏振相关损耗进行控制与补偿的方法，实现偏振模式的高效调控，达到提高硅基光波导集成器件的信息处理带宽和降低其调控功耗的目的。在我们已成功研制出硅基10GHz电光调制器和亚ns电光开关的工作基础上，本研究将通过创新硅基电光器件的调制机理和设计结构，引入高效的偏振模式控制方法，并发展其集成制造工艺技术提升器件性能，从而有效调控器件中的偏振模式差异，使高速率硅基光波导集成器件实现可调控的偏振相关性，促进硅光子集成芯片的应用。

高速率硅基光波导集成器件已成为半导体光子学的研究热点。目前此类器件偏振相关损耗显著，模式控制效率低，限制了这些器件的实用化发展。为降低集成器件的偏振相关性和实现对其灵活控制，必须深入研究其偏振模式的调控机理。本项目以硅基光波导集成器件中波导特性、电光效应、器件结构、调制原理等方面的偏振模式调控机理及应用方法为主要研究内容，研究了低偏振相关性、低损耗、低串扰的宽带无源光路耦合器，在设计时有选择地控制偏振模式，实现偏振分离，用于光调制器和光开关的内部结构单位、显著地改善这些器件的附加损耗、空间不均衡性、偏振相关性等关键性能，进一步还研究了硅基电光调制器件实现低功耗、单偏振、模式可调的关键问题，分析并实施了改进的工艺手段，获得了良好的加工流片结果。在全面分析偏振模式的物理机制和相关效应的基础上，着重探索偏振模式及其调控效率对器件电光效应等方面的影响，研究出对偏振相关损耗进行控制与补偿的方法，实现偏振模式的高效调控，达到提高硅基光波导集成器件的信息处理带宽和降低其调控功耗的目的。项目重点关注复杂模式的传输问题，重点研究如何在有源器件中利用无源结构单元实现偏振模式的调控、变换，合理利用三维光子波导结构中偏振模式的多样性和相关损耗特性，利用超模原理实现单一偏振态高速率有源器件，成功研制出带宽大于50GHz 、速率大于80Gbps的硅基电光调制器和100ps 量级电光开关。此外，本项目在与其他国家基础研究计划的支持下，相继开展了高速光开关阵列、光调制器、光探测器、片上光链路的研究工作。