【作者】 张韬；

【导师】 崔继文；

【作者基本信息】 哈尔滨工业大学 ， 仪器科学与技术， 2011， 硕士

【摘要】 随着光纤技术的迅猛发展,光纤传感器在传感器领域中占据了很重要的位置。光纤传感器的光源通常是气体激光器、半导体激光器等相干光源,而相干光源由于其自身的光束特性,极容易在光纤端面形成干涉,这也给光纤传感器的后期的信号处理带来了极大的不便。因此,若实现非相干光源的光纤耦合,可以消除光纤传感器中由于模间干涉产生的噪声,提高光纤传感器的信噪比,成为一个急需解决的问题。本文从光源与光纤的基本耦合原理出发,对影响非相干光束光纤耦合的若干因素进行了分析,从压缩光束发散角,提高光束能量集中程度以及针对提高光纤耦合效率的光纤端面处理方法进行了研究。主要包括以下几方面内容:从提高光纤耦合效率的角度入手,对光纤端面结构与光纤数值孔径的关系进行了理论研究,对光纤端面结构的处理方法进行了详细的分析,并针对多种光纤结构的耦合试验结果进行了对比分析。对非相干光-光纤耦合系统进行了设计,通过基本光学设计理论确定了光纤耦合系统的初始参数,透镜类型以及基本相差容限。使用ZEMAX光学仿真软件对光学系统初始参数进行优化,并通过软件的仿真结果光学系统的性能作出了评价。利用ZEMAX软件对光学系统进了公差分析,保证光学系统在现有的加工精度和装配精度上依然可以实现预期的功能指标。对本文中设计的光纤耦合光学系统进行了加工、装配。调试了光纤耦合模块,完成对不同光纤光纤耦合方式的对比,实验中光纤出射端最高功率可以达到132.0μW。实验表明,采用本文设计的非相干光光纤耦合模块进行光纤耦合,光纤出光端光功率从之前的53.6μW上升至132.0μW,本文中研究设计的光纤耦合光学系统,以及提高光纤数值孔径方法均在很大程度上提升了光纤耦合效率,为进一步提升光纤传感器的性能提供了一种技术途径。更多还原

【Abstract】 With the fast development of the optical fiber technology, the optical fiber sensor plays a very important role in the sensing area. Usually the fiber-coupled light sources used in the optical sensor are gas lasers, semiconductor lasers and other coherent light source. Because of its beam characteristics, it is very easy for coherent light to interference in the fiber-coupling process; this also has brought a great inconvenience in the signal processing. Therefore, to realize the fiber coupling of incoherent light, to eliminate the noise due to the inter-mode interference, and to improve the SNR of fiber optic sensors become urgent tasks. Starting from the basic principles of coupling between light and fiber, we analyze several factors which affect the coupling. From the aspect of compressing beam divergence angle, concentrating beam energy and fiber end surface processing approach to enhance the efficiency of optical fiber-coupled. The main works of the paper are as follows:First, we study the relationship between the structure of the fiber end surface and the fiber numerical aperture with respect to the improvement of the efficiency of fiber coupling. In particular, we analyze the processing method for the structure of the fiber end face in detail and we compare the results with different fiber structures.Next, we design incoherent optical fiber coupling system, employing the basic optical designing theory to decide the initial parameters of fiber-coupled system, lens type and fundamental differential tolerance. Using the ZEMAX to optimize the initial parameters of the optical system and evaluate the performance of the optical system. We also analyze the tolerance to ensure that we can still realize the anticipated function index with the existing machining precision and assembly accuracy.Finally, we process and assemble the optical system which was designed above. We also debug the fiber-coupled modules and make the contrast of different couple pattern. In our experiment, we reach the exit power up to 132.0μW.Experiments show that using this design of the incoherent light fiber-coupling module for coupling, the effluent light power of the effluent fiber increases from the previous 53.6μW to 132.0μW. The fiber-coupling optical systems proposed in this paper and the fiber numerical aperture improving methods are greatly enhance the optical coupling efficiency, which provide a technical way to further improve the performance of fiber optic sensors.更多还原