有机聚合物电光调制器的设计与实验研究

【作者】 李晨；

【导师】 蒋亚东；

【作者基本信息】 电子科技大学 ， 光学工程， 2008， 硕士

【摘要】 Mach-Zehnder光波导电光调制器是重要的集成光学器件,在民用,国防,科研等领域都起着重要的作用。有机非线性电光聚合物具有电光系数大、易于制备、与半导体工艺兼容、在红外到毫米波波段色散小、响应速度快等优点,已经成为集成光学器件发展的有力推动力量。基于非线性有机聚合物光波导的Mach-Zehnder(M-Z)电光强度调制器目前已经成为各国研究的热点。本文比较全面地介绍了聚合物电光调制器的发展现状以及未来的发展趋势,然后对基于有机电光聚合物光波导的M-Z强度调制器的制作工艺,理论,测试三个方面做了详细的研究:对聚合物波导的主要工艺步骤进行了详细的研究。利用真空热蒸发的方法在硅基片上制备了波导下电极;用旋涂的方法制备了聚合物下包层;利用聚合物薄膜电晕极化系统对一种新型生色团DCDHF-2-V和聚甲基丙烯酸甲脂(PMMA)主客掺杂型电光聚合物进行了极化实验;初步研究了针对下包层材料的反应离子刻蚀工艺,并通过对刻蚀样品的台阶仪测试得到了一系列实验参数。这些工作为制作聚合物波导强度调制器的原型器件提供了实验基础。分别利用两种方法对泰勒级数展开法进行了算法优化和编程实现,并对实际聚合物光波导调制器进行了二维模拟,分析了不同参数下光在M-Z调制器结构中TM基模的模场分布,并得到了以损耗最小为依据的优化结果。还利用二维宽角度Padé方法对对调制器进行了编程实现和模拟,并对比了两种方法的结果。接下来又将Padé方法扩展到三维,不仅得到了波导中横截面TM模基模的模场分布,而且还直观的给出了由于模式形状失配而产生的能量损耗过程。利用基于简单发射法的聚合物薄膜电光系数测量系统对极化样品进行了测量,但结果明显偏小,随后又对误差产生的原因进行了详细的分析;其次利用棱镜耦合法对波导样品进行了折射率和厚度的测量并利用MATLAB软件实现了求解折射率和厚度的数值方法。更多还原

【Abstract】 Optical intensity modulator based on Mach-Zehnder waveguide is an important device of Integrated Optics and plays an important role in the field of civilian use, defense,and scientific research.Nonlinear organic E-O polymer has a high E-O coefficient,low fabrication difficulty,compatibility with semiconductor techniques, small dispersion in infrared to millimeter band,fast response and is therefore regarded as an important driving force for the development of integrated optical device. Mach-Zehnder(M-Z) E-O intensity modulator based on nonlinear E-O polymer waveguides is an attractrive research area for many countries.The current development and the prospect of polymer-waveguide-based devises were introduced at first.Then the theory,fabrication techniques and measurement methods were studied systematically.The major processing steps of polymer waveguide were studied.The sub-electrode is deposited with the vacuum thermal evaporation technique;the lower cladding layer was obtained by spin-casting;the polling system for polymer thin film was used and experiments are conducted on the sample of the host-guest system of a novel chromophore DCDHF-2-V and PMMA;the Reactive Ion Etch for processing the lower cladding was studied preliminarily and results were obtained with surface profilometry. These works give a solid foundation for the final realization of the prototype of polymer waveguide M-Z modulator.A numerical method based on the Taylor Series Expansion method was optimized by two methods,realized and will be applied to a real design.The fundamental TM mode distribution in the M-Z modulator with various parameters was analysied,and the optimized result based on the minimum optical power loss was obtained. Two-dimensional simulation employing Padémethod was also realized and the results of the two methods were compared.By expanding the Padémethod to 3-dimension case, the distribution of the fundamental TM mode of the cross section was obtained and a direct view of how the optical power caused by the mode mismatch is lost in the propagation was also obtained. A system for measuring the E-O coefficient based on the Simple Reflection Method is used to test a polled sample.However,the result was much lower than the reported value,therefore,the possible cause of the difference was analyzed;a waveguide sample is tested with the Prism Coupling Method and the refractive index and thickness is solved numerically using a program designed with Matlab.更多还原