铌酸锂低半波电压调制器研究

发布时间：2018-11-24 18:29

【摘要】：电光调制器在光通信、光传感与光信息处理领域具有重要的应用价值,是这些系统的关键器件之一。目前,电光调制器基本上都是使用无机晶体铌酸锂(LiNbO3,LN)材料制作,这是因为LN具有较大的电光系数,在较宽的波长范围(450 nm-4500 nm)内具有良好的光学透明性,以及具有成熟的波导制作工艺。在电光调制器的应用中,为了降低系统的功耗,提高器件的性能,以及方便地实现与系统的其他部分集成,通常要求电光调制器具有低的半波电压。因此,在电光调制器的研究领域,降低器件的半波电压是一个重要的研究方向。为了实现低的半波电压,对LN电光调制器而言,最有效的办法是使用较长的电极,从而增加电光作用区长度,但这不可避免地会增加器件的长度,不利于器件的制作与系统的集成。此外通过优化波导与电极的设计,如采用脊形光波导增大调制电场与光场的重叠积分也是降低半波电压的一种方法,但这将导致复杂的工艺,而且对半波电压的降低也十分有限。因此,本论文针对降低LN电光调制器的半波电压进行研究,探索了利用反射结构实现低半波电压的原理,并以x切y传的LN晶体为材料,通过退火质子交换的方式,研究了反射式LN电光调制器的制作工艺及相关测试技术。论文的主要工作及成果如下:1.研究了反射型LN低半波电压电光调制器的基本原理首先对LN相位调制器、马赫-曾德尔(Mach-Zehnder,M-Z)干涉仪强度调制器的基本原理进行了分析,然后在此基础上讨论了降低LN调制器的半波电压的方法,并分析了反射型LN低半波电压电光调制器的基本原理。此外,通过对LN光波导的两个端面镀膜制作了波导型法布里-珀罗腔(Fabry Pérot,F-P),并对其传输特性进行了研究。2.退火质子交换LN光波导的理论分析与制作工艺研究首先利用有效折射率法研究了LN光波导的设计,确定了单模LN光波导的参数;然后研究了基于退火质子交换制作LN光波导的工艺技术,经大量实验后得到了制作出合格的LN单模光波导的工艺条件;最后,进一步通过对波长为1538.3 nm时LN有效折射率的研究来优化实验参数,并重点研究了交换时间及退火时间对光波导的影响,最终得到了实现低损耗LN光波导的工艺条件。3.LN反射型电光调制器的设计、制作及测试根据反射型LN电光调制器的工作原理,设计了相应的器件结构参数;根据这些参数制作了相应的光刻掩模版;利用退火质子交换工艺制作了反射型LN相位调制器、强度调制器及LN光波导F-P腔;搭建了测试平台,分别测试了LN调制器的光学特性,电光调制特性及半波电压,其结果表明所设计的反射型LN电光调制器可实现4 V的半波电压,此外,对腔长800μm的LN光波导F-P腔的传输谱特性进行了测试。
[Abstract]:The electro-optic modulator is one of the key devices in optical communication, optical sensing and optical information processing. At present, electro-optic modulators are basically made of inorganic crystal lithium niobate (LiNbO3,LN) because LN has a large electro-optic coefficient and good optical transparency in a wide wavelength range (450 nm-4500 nm). And has mature waveguide fabrication technology. In the application of electro-optic modulator, in order to reduce the power consumption of the system, improve the performance of the device, and easily integrate with other parts of the system, the electro-optic modulator is usually required to have a low half-wave voltage. Therefore, in the field of electro-optic modulator, reducing the half-wave voltage is an important research direction. In order to achieve low half-wave voltage, the most effective method for LN electro-optic modulator is to use a longer electrode to increase the length of the electro-optic action zone, but this will inevitably increase the length of the device. It is unfavorable to the fabrication of the device and the integration of the system. In addition, by optimizing the design of waveguides and electrodes, such as increasing the overlap integral between modulated electric field and light field by ridge waveguide, it is also a method to reduce half-wave voltage, but this will lead to complex process. And the reduction of half wave voltage is very limited. Therefore, in this paper, we study the reduction of half-wave voltage of LN electro-optic modulator, and explore the principle of realizing low half-wave voltage using reflection structure. The LN crystal with x cut y is used as material, and the way of proton exchange is annealed. The fabrication technology and related testing technology of reflective LN electro-optic modulator are studied. The main work and results are as follows: 1. In this paper, the basic principle of the reflected LN low half-wave voltage electro-optic modulator is studied. Firstly, the basic principles of the LN phase modulator and the intensity modulator of the Mach-Zehnder,M-Z interferometer are analyzed. Then, the method of reducing half-wave voltage of LN modulator is discussed, and the basic principle of reflected LN low-half-wave voltage electro-optic modulator is analyzed. In addition, the waveguide Fabry-Perot cavity (Fabry P 茅 rot,F-P) has been fabricated by coating two ends of the LN optical waveguide, and its transmission characteristics have been studied. 2. Theoretical Analysis and Fabrication Technology of annealed Proton Exchange LN Optical waveguides the design of LN optical waveguides is studied by using the effective refractive index method and the parameters of the single-mode LN optical waveguides are determined. Then the fabrication technology of LN optical waveguide based on annealed proton exchange is studied. After a lot of experiments, the process conditions of making qualified LN single-mode optical waveguide are obtained. Finally, the experimental parameters are optimized by studying the effective refractive index of LN at a wavelength of 1538.3 nm, and the effects of switching time and annealing time on the optical waveguide are studied. Finally, the process conditions of realizing low loss LN optical waveguide are obtained. The design of 3.LN reflective electro-optic modulator is given. According to the working principle of reflective LN electro-optic modulator, the corresponding device structure parameters are designed. The photolithography mask is made according to these parameters, and the reflective LN phase modulator, intensity modulator and LN optical waveguide F-P cavity are fabricated by using the annealing proton exchange process. The optical characteristics, electro-optic modulation characteristics and half-wave voltage of the LN modulator are tested. The results show that the reflected LN electro-optic modulator can achieve a half-wave voltage of 4 V. The transmission spectrum characteristics of an 800 渭 m LN optical waveguide F-P resonator are measured.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN761

【共引文献】