【作者】 杨冰；

【导师】 杨建义；

【作者基本信息】 浙江大学 ， 微电子与固体电子学， 2014， 博士

【摘要】 波长是光波的一个基本物理参量,对光波长的解析(Wavelength Measurement/Interrogation)是光学系统中的一种基本功能需求。尤其是在光纤光栅传感系统、密集波分复用光通信系统以及光互连系统中,波长解析都扮演着重要的角色。对于光波长解析技术的研究具有重要的理论和现实意义。波长解析技术就是通过测量与波长有一定对应关系的其他物理量,进而由函数关系给出波长或者波长变化量的一种解析方法。现有的光波长解析技术有很多的类型,但是大部分都需要使用比较大型、笨重的设备,或者是需要搭建复杂的光路系统并配备较多的辅助器件来实现。这些方法普遍存在使用不便、不利于携带、体积大、重量大、解析速度慢、能耗高等缺点。对于日益发展的集成光学系统来说,这些方法大部分是不适用的。在诸多波长解析方法中,基于边缘滤波器滤波特性的比率制波长解析方法(Ratio-metric Wavelength Measuring Method)具有结构简单、解析速度快、功耗低、使用方便、不需要机械调节、可以用集成光波导来实现等优点,是比较有潜力的集成化波长解析器件(Intergrated Wavelength Monitor)的实现方案之一。本文的研究目的就在于设计和制作基于集成光波导且可以在集成光学系统中使用的波长解析器件。我们分别利用玻璃基离子交换光波导和硅基光波导设计并制作了不同结构的比率制波长解析器件,并且对器件的各方面性能进行了详细的测试和分析。论文的主要创新点包括：1.设计和制作了基于玻璃基离子交换光波导的“X”型波长解析器件。该器件利用非平衡的马赫曾德干涉仪(Mach-Zender Interferometer, MZI)结构来构成边缘滤波器,采用电场辅助下的两步离子交换工艺来制作。器件由两个MZI组成,通过对MZI参数的设计和离子交换工艺中参数的调整来保证器件的输出形成“X”型波长响应结构。“x”型波长响应结构可以有效的提高比率制波长解析器件的分辨率。非封装测试的条件下,在54nm的范围内波长解析分辨率可以达到0.1nm以上。如果是经过封装的器件,理论上的分辨率可以达到15pm以上。由于玻璃基离子交换光波导具有良好的保偏特性,器件的偏振依赖性比较小,偏振带来的波长解析误差小于0.5nm,与光纤型比率制波长解析器件的数据接近。器件长度约为26mm,可以做到无源工作,即时解析。相对于一般的波长解析方法而言,具有体积小、速度快、功耗低的特点。2.设计和制作了基于玻璃基离子交换光波导的两级波长解析器件。由于比率制波长解析方法原理上的限制,器件的分辨率与解析范围通常是相互制约的。因此,为了在提高器件分辨率的同时保证器件仍然具有较宽的工作范围,可以采用两级波长解析结构。我们设计和制作了基于玻璃基光波导的两级波长解析器件。在单级解析器件的基础上增加了一对梳状滤波器,用来进行第二级高精度的波长解析。通过两级解析,器件在保持了第一级解析较大的工作范围的同时,波长解析分辨率可以提高到10pm以上。3.设计了基于硅基光波导微环谐振腔结构的比率制波长解析器件。与玻璃基波长解析器件相比,基于硅基光波导的比率制波长解析器件拥有更小的尺寸,可以方便地被集成在硅基光子学系统中。我们设计了基于硅基光波导微环谐振腔的波长解析器件。器件采用“X”型波长响应结构,将微环谐振腔作为边缘滤波器,通过对微环设计参数的调整来保证器件输出符合“X”型波长响应。器件采用CMOS (Complementary Metal-Oxide Semiconductor)兼容的半导体加工工艺制作,基底材料为SOI (Silicon on Insulator)。芯片上集成了加热电极来对微环的谐振波长进行调节,通过这种方法实现器件的工作范围可调。器件的测试的结果,在1.2nm的工作范围内,非封装条件下测试的分辨率高达5pm。理论上封装测试的结果可以接近2pm。器件的有效尺寸仅为120μm×150μm。在拥有极高分辨率的同时具有非常小的尺寸。不仅可以单独地作为高分辨率波长解析器件使用,还可以作为精解析器件,与粗解析器件集成,构成一个集成型高性能波长解析器件。更多还原

【Abstract】 Wavelength is a fundenmetal characteristic of the lightwave. Wavelength measurement is a basic and important requirement in optical communication system, especially in the fiber Bragg grating (FBG) based optical sensing systems, the multichannel dense wavelength-division multiplexing (DWDM) optical communication systems, and the optical interconnect system.In order to measure the wavelength of the signal light, we need to measure a physical quantity which is related to the wavelength, and then demodulate the measurement results to get the wavelength. There are many methods to measure the wavelength of the light, but most of them are cumbersome, bulky, slow, and power costly. As a result, they are insuitable for the integrated optical system. The purpose of the thesis is to demonstrate wavelength monitors fabricated with integrated waveguides which can be used in integrated optical system.Among all the methods for the wavelength measurement, the ratio-metric wavelength measuring method, which is based on the filter characteristic of the edge filter, is the most potential technique which can be realized by using the integrated waveguides. The ratio-metric wavelength monitor has the advantages of simple configuration, high-speed measurement, low power consumption, and no mechanical movement. We designed and fabricated ratio-metric wavelength monitors based on ion-exchange waveguides on glass and silicon-based waveguides on SOI (silicon on insulator) substrate. The wavelength measurement performance of the devices are measured and analysed. The main works are listed as follows:1. Dual Mach-Zender Interferometer (MZI) based integrated X-type ratio-metric wavelength monitor on glass. We design and fabricate an integrated ratio-metric wavelength monitor based on ion-exchange waveguides on glass. The device consists of two unbalanced MZIs acting as edge filters. They are designed to have "X-TYPE" spectral response. The output ratio of them is monotonic to the wavelength in the functional range of the wavelength monitor. The measured resolution is about0.1nm ranging from1522to1576nm, which can potentially be improved to15pm after packaged. The polarization dependency of the device is also discussed. Our work makes it possible to build a high performance integrated sensing and detecting optical system on one single chip.2. Ratio-metric wavelength monitor with a double measurement structure. The measureable wavelength range and the resolution of the ratio-metric wavelength monitor are limited by each other in a conventional structure. A double measurement structure is demonstrated in order to overcome this problem. We designed and fabricated a high performance integrated ratio-metric wavelength measurement device on glass by the method of ion-exchange. It contains a rough wavelength measurement with wide range and a fine wavelength measurement with high resolution. The device is consisted by four unbalanced MZIs. The highest measured resolution can reach0.01nm. By heating the unbalanced MZI, the performance of the fine wavelength monitor can be improved.3. Microring based ratio-metric wavelength monitor on silicon. Compared to the ion-exchange waveguides, the size of the optical devices fabricated with the silicon-based waveguides is very small. The wavelength monitor based on silicon-based waveguides can be used in integrated optical system convienetly. An integrated dual-ring ratio-metric wavelength monitor (DR-RMWM) with ultra high wavelength resolution and compact size is demonstrated. Two microrings are used as the edge filters and designed to achieve an "X-TYPE" spectral response in a particular wavelength range. It is fabricated with the CMOS (Complementary Metal-Oxide Semiconductor) compatible fabrication process on the silicon-on-insulator (SOI). The measured wavelength resolution is5pm in a1.2nm wide wavelength range. The effective scale of the device is only120×150μm.By tuning the resonant wavelength thermally, the functional wavelength range can be shifted. The DR-RMWM can find applications in wavelength monitoring systems, especially the on-chip systems.更多还原