一种集成了光功率监测功能的硅基载流子耗尽型微环调制器

Silicon carrier-depletion microring modulator is a key component in optical interconnect systems. Due to its resonance nature and the thermal sensitivity of the silicon waveguide, the silicon microring modulator should be integrated with a optical power monitor so as to dynamically control the operation wavelengh. This project proposes a scheme which integrates a silicon carrier-depletion microring modulator and a power monitor without introducing any absorption materials or adding any additional processing steps. By controlling the overlap of P-type and N-type ion implantation windows, a dopant compensated intrinsic region with lattice defects is implemented inside the waveguide at the power monitoring area. The photocarriers are then generated by the defect mediated absorption. The project will investigate the property of the dopant compensated intrinsic SOI waveguide, study the relationship between the doping level, defect density, optical propagation loss and photon-to-electron conversion quantum efficiency. After that, the project will improve the responsivity of the power monitor by optimizing the device design and the processing condition, as well as by leveraging the current avalanche multiplication mechanism. According to the performance of the final device, a feedback mechanism to control the operation wavelength of the microring modulator will be established and implemented with the specific circuit. The target of the project is to demonstrate a microring modulator which operates at a bit rate of 20 Gb/s with a driving voltage of less than 2 Vpp while the ambient temperature fluctuates within a range of 10 K. The realization of this project will propel the practical application of the silicon carrier-depletion microring modulator.

硅基载流子耗尽型微环调制器是光互联系统中的关键器件,其谐振特性和硅波导的温度敏感性，决定其必须与功率监测器集成，从而动态控制工作波长以实现稳定工作。本项目提出一种二者的集成方案，不需要引入新的吸收材料或增加工艺步骤，即能在载流子耗尽型微环调制器上集成功率监测功能。它控制离子注入时P型和N型注入窗口的交叠，在功率检测区波导中形成含晶格缺陷的掺杂补偿型本征区，通过缺陷态吸收产生光生载流子。本方案拟研究掺杂补偿型SOI波导的性质，揭示标准CMOS流程下，补偿掺杂水平、缺陷态密度、光传输损耗、光电转换量子效率之间的联系机制。在此基础上通过器件结构优化和引入电流增益机制，增强光电转换效率。最后根据器件性能，确定控制微环调制器工作波长的反馈机制并电路实现。最终实现一种速度大于20 Gb/s,驱动电压小于2伏，在温度扰动10度时仍能正常工作的微环调制器。该项目的实现将能推动硅基微环调制器的最终实用。

本项研究仅仅围绕高性能硅基微环调制器展开：针对谐振型调制器对工作条件敏感，需要对工作状态进行实时监控的特点，设计和制作了基于缺陷态吸收的包含了功率监测功能的硅基载流子耗尽型微环调制器；深入研究了补偿掺杂增强缺陷态吸收的机制，并在实验中明确观察到了补偿掺杂能增强光电流并且减小光传输损耗，系统地分析测试了补偿掺杂区不同离子注入条件以及不同宽度对功率监测器性能的影响；对微环调制器中光子的动态响应行为进行了理论建模和详细的理论分析，并得到了实验结果的验证；在此基础上，提出利用双环结构和推挽驱动方式提高常规微环调制器的性能；基于微环器件，实现了微波倍频以及微波频率测量等一系列微波光子学中的必须功能。