【作者】 邱晨；

【导师】 杨建义； 王明华； 江晓清；

【作者基本信息】 浙江大学 ， 微电子与固体电子学， 2013， 博士

【摘要】 微环谐振腔是一种非常巧妙的谐振结构,它利用光波导构成光学回路形成反馈,从而对某些特定波长的光的输出产生影响。相对传统的光学结构微环谐振腔具有结构简单、集成度高的特点。以绝缘衬底上的硅材料(Silicon-on-insulator, SOI)为平台制作微环器件,工艺与CMOS工艺相兼容,大规模生产可以极大地降低光子器件的成本。具有差异才能产生信息,所以可调特性应是信息器件所必备的核心特性。硅材料具有良好的热光效应和载流子色散效应：利用热光效应,可以对硅的折射率大范围调节；利用载流子色散效应,可以实现高达数十GBit/s的高速调制。长期以来人们对硅基微环的基本特性进行了广泛而深入的研究,但是应用的多样性需求对基于硅材料微环集成芯片的研究来说仍是一项极富挑战性的课题。本论文主要以硅基微环谐振腔为基本单元,利用其可调效应,对集成光链路、集成光传感器以及传感解调器等若干光电子器件进行理论设计和实验研究。其主要创新和特色工作在于：1.针对目前光互连领域对于通信容量和速度的需求,提出了基于微环结构的可重构光学链路的概念,通过热光效应,对微环调制器和滤波器的工作波长进行控制。这种结构一方面可以利用工作通道的可重构特性使同一物理光链路在不同时刻工作在不同波长通道,提高光波分复用系统的灵活性和通道利用效率,非常适合应用于波分复用系统当中；另一方面,微环的工艺制作误差可以通过热光效应得到补偿,使信道的误码率和通道间的串扰得到改善。此外,这里所提出的可重构光链路中的微环调制器采用等离子体色散型电极,确保了对信号的高速调制；并且,光链路中的滤波器为二阶串联微环结构,解决了传统一阶微环滤波器带宽较窄,串扰过高的弊端。进一步地,本论文利用新加坡微电子研究所提供的CMOS兼容工艺对提出的器件进行了制作和测试,制作的光链路中微环调制器和滤波器分别以3.9mW/nm和5.9mW/nm的加热效率实现了在0.8nm波长间隔的通道之间的重构,且利用热光电极实现的通道切换速度达到5kHz；此外,由于采用了二阶串联双环结构滤波器设计,所形成通道的3-dB带宽等于0.57nm,通道间串扰小于-20dB。2.针对高性能传感器的应用需要,提出利用眼型微环嵌套结构的非对称Fano谐振特性提高基于微环的光学传感分辨率和探测范围。本论文利用转移矩阵法和时域有限差分法对这一结构所形成Fano谐振的物理本质和特性进行了深入的研究,指出利用眼型微环嵌套结构的非对称Fano谐振可以在相同的插入损耗下有效地提高下路端光谱尖锐度；并且该结构还可以大幅度提高下路端光谱的消光比。为了使该理论在实践上得到证明,本论文利用比利时IMEC硅光子工艺线制作了眼型微环嵌套结构并与传统的一阶上下路微环滤波器的谐振特性做了对比。结果表明：眼型嵌套微环结构下路端光谱的尖锐度相对传统的一阶上下路微环滤波器提高了约3倍,消光比提高了约20dB。光谱尖锐度的提高意味着在同样的测试条件下能够分辨更小的光谱移动,提升了波长调制型传感应用中的传感分辨率；而消光比的提高则提升了强度调制型传感应用中的传感探测范围。在此基础上,本论文基于硅材料的热光可调效应,利用制作的眼型嵌套微环结构成功地对温度进行了传感。这一工作不仅有助于理解Fano谐振的形成原理,它对于拓展Fano谐振的应用领域也具有重要意义。3.论文还提出了一种基于可调微环滤波器的传感解调器,这种解调器利用热光效应调谐微环滤波器的输出光谱,对波长调制型传感器的输出光谱进行扫描,通过读取系统输出功率最大时所对应的加热功率,得到相应的波长调制型传感器的中心波长。论文在SOI材料上制作了这种微环解调器,并成功地对FBG温度传感器的布拉格波长和片上微环滤波器的中心波长进行了解调。相较于传统的基于分立光学器件的传感解调系统,本论文所提出的微环解调器具有尺寸小、成本低、适宜于高密度集成的优点。更多还原

【Abstract】 Silicon is a Group IV semiconductor element. Silicon material, which is widely used for the electronic and photonic device fabrication, acquired the dominance status in the modern electronic industry due to its physical and chemical properties. Since advantage of the CMOS compatible fabrication processes, silicon-on-insulator (SOI) is the most promising platform for integrated photonic devices.Microring resonator, which is formed by a single closed-loop waveguide, is a very clever resonance scheme. It is suit for lot kinds of optical applications, such as the lasers, the optical sensors, and the multiplexer/de-multiplexer. The information is produced by the differences, so the tunable character is the key character for the information function devices. Silicon has excellent thermo-optic and plasmonic dispersion effect:large range tuning could be achieved by the thermo-optic effect; tens of Gbit/s high speed modulation would be realized by the plasmonic dispersion effect. This paper focus on the silicon microring based devices. The reconfigurable optical link, integrated microring sensor and interrogator is demonstrated both theoretically and experimentally. This thesis makes innovative works mainly in the aspects as follows:1. A channel-selectable optical link based on silicon microring resonator is proposed and demonstrated. This optical link consists of the wavelength-tunable microring modulators and the filters, defined on a silicon-on-insulator (SOI) platform. With a p-i-n junction embedded in the microring modulator, light at the resonant wavelength of the ring resonator is modulated. And the2nd-order microring add-drop filter routes the modulated light. The channel selectivity is demonstrated by heating the microrings. With a thermal tuning efficiency of5.9mW/nm, the filter drop port response was successfully tuned with0.8nm channel spacing. We also show that modulation can be achieved in these channels. This device aims to offer flexibility and increase the bandwidth usage efficiency in optical interconnection. 2. The Fano resonance in the’eye-like’microring resonator system (EMRS) is theoretically and experimentally investigated. The asymmetric Fano-resonance line shape of EMRS is generated by adding a microring inside and coupling with the outer ring to produce a nonlinear phase shift. The EMRS was fabricated on silicon-on-insulator wafer by the complementary metal-oxide-semiconductor compatible process. Compared to the conventional single-stage microring add-drop filter structure, the maximum sharpness of the transmission of the drop port is enhanced3times, and the drop port extinction ratio is increased by about20dB. The experimental results are in good agreement with the theoretical analysis.3. A wavelength-modulated optical sensor interrogation system based on tunable microring filter has been proposed and demonstrated both theoretically and experimentally. The wavelength shift of the sensors can be readout from the shift of the peak optical output of the system by scanning the resonant wavelength of the microring filter. We fabricated the interrogator on the silicon-on-insulator platform and a fiber Bragg grating sensor was precisely interrogated. Such a technique potentially provides a compact, low-cost, and high-performance approach for the interrogation of the wavelength-modulated sensor and distributed sensor arrays.更多还原