光电系统实验室知识库

第一章介绍了片上多核处理器光学互连的发展和作为光学互连理想平台的硅基光子学的发展，其中着重介绍了高速硅基光学调制器的发展历程。本章最后大致介绍了本文的主要研究内容和创新点。

第二章系统的介绍了载流子注入型硅基Mach-Zehnder光学调制器的设计，主要分为两个部分。第一部分介绍了无源光学结构的设计，主要介绍了无源1´2光学分束器、2´1光学合束器的设计以及Mach-Zehnder干涉仪两臂臂长差的设计。Mach-Zehnder干涉仪两臂臂长差值直接决定了器件的光学带宽，通过采用等臂结构和两臂同时掺杂设计仿真结果显示此时器件的静态光谱在1.5 mm~1.6 mm呈现出良好的平坦性，这说明器件具有很大的光学带宽。第二部分介绍了调制区电学结构的设计，主要着眼于提高器件调制效率和电学响应速度。由于载流子注入型硅基Mach-Zehnder光学调制器频率响应带宽受限于大的少数载流子寿命，本部分的设计对于最终改善器件的高速调制性能并不明显，但是本部分的分析对于器件工作原理的理解至关重要，对于开展器件高速调制实验测试有很大帮助。

第三章介绍了载流子注入型硅基Mach-Zehdner光学调制器的制作工艺，器件的制作工艺简单、与CMOS标准工艺完全兼容。

第四章系统的阐述了载流子注入型硅基Mach-Zehnder光学调制器的测试表征，主要分为两个部分。第一部分主要介绍器件高速调制实验测试系统，主要着眼于介绍通过对高速数字驱动信号的频谱特性进行改造来提高器件的调制速率。第二部分给出了实际器件测试实验结果，包括NRZ码预加重高速数字信号驱动下的高速调制实验结果和RZ码高速数字信号驱动下的高速调制实验结果。此外本章通过实验证实了等臂结构器件在整个C波段具有平坦的传输光谱，且器件在整个C波段实现了12.5 Gb/s的高速调制性能，高速调制消光比均大于7 dB。

最后一章对全文进行总结，并对后续工作进行了展望。

    With chip multiprocessor (CMP) continuously demanding more communication bandwidth, metallic-based interconnect gradually becomes the bottleneck for improving the performance of CMP due to its higher power consumption, limited bandwidth and longer latency. Optical interconnect based on silicon photonics is considered as a potential solution to overcome the limitations of its electrical counterpart. As a device transforming data from electronic domain to optical domain, optical modulator is the core module of optical interconnects. The objective of the thesis is to develop carrier-injection silicon Mach-Zehnder optical modulator with modulation speed >10 Gb/s and dynamic extinction ratio >7 dB. In this paper, design, fabrication, and characterization of carrier-injection silicon Mach-Zehnder optical modulator are systematically discussed.

    In chapter 1, the development of optical interconnects for CMP and silicon photonics are introduced, in which we put emphasis on the development of high-speed silicon optical modulators. The research content and innovation points of the thesis are given at the end of the chapter.

    In chapter 2, design of carrier-injection silicon Mach-Zehnder optical modulator is discussed comprehensively. It is divided into two parts. In the first part, design of optical 1´2 splitter, 2´1 combiner and length-difference value between the two arms of Mach-Zehnder Interferometer (MZI) structure are discussed. The length difference determines optical bandwidth of the device and simulation results indicate that devices with balanced MZI structure and doping on both arms have flat transmission spectra in the wavelength range between 1.5 mm~1.6 mm. It means that the devices have large optical bandwidth. In the second part, design of carrier-injection electrical modulation structure is discussed, which focuses on increasing modulation efficiency and modulation speed. Since the frequency response bandwidth of carrier-injection optical modulator is limited by the large minority carrier lifetime, the design in this part cannot increase high-speed modulation performance of the device obviously. However, it is of vital importance to the understanding of the operating principle of PIN diode, which is helpful for the high-speed modulation experiments.

    In chapter 3, fabrication processes of carrier-injection silicon Mach-Zehnder optical modulator is introduced, which is simple and totally compatible with standard CMOS process.

    In chapter 4, the test and characterization of carrier-injection silicon Mach-Zehnder optical modulator is discussed systematically. It is divided into two parts. In the first part, we introduce the high-speed experimental systems of the device, in which, we focus on engineering frequency spectrum of NRZ electrical drive signal to increase modulation speed of the device. In the second part, experimental results of the fabricated devices are given, which includes the high-speed diagrams under NRZ electrical pre-emphasized drive signal and RZ electrical drive signal. Furthermore, experimental results on devices with balanced MZI structure are also given, the devices works well in the whole C-band at 12.5 Gb/s with dynamic extinction ratio >7dB.

    The last chapter summarizes the thesis and gives guidance for future works.