An on-line fiber cutting-welding method for the fabrication of Fabry-Perot micro-cavity

A Fabry-Perot micro-cavity is fabricated by on-line fiber cutting-welding method. The asymmetrical fiber Fabry-Perot micro-cavity is designed and produced by cutting a standard single-mode fiber and welding the fiber end with the core-offset structure. The length of the Fabry-Perot micro-cavity could be controlled within a certain range of accuracy based on the on-line fiber cutting-welding method. According to this method, a micro-machined Fabry-Perot micro-cavity with a length of about 147 μm is achieved and its spectral characteristic is also investigated in our experiment. This proposed method is suitable to produce a micro-fiber-optic structure with improved and controlled precision, which is attractive for the fiber processing field. Moreover, the fabricated Fabry-Perot micro-cavity also has potential application in the microfluidic system and biochemical detection area.     

Fiber-coupler-based microfluidic system for trapping of DNA biomolecules

A miniature fiber-coupler-based microfluidic system is proposed for trapping of DNA biomolecules. The loop-shaped fiber-coupler is fabricated by using flame tapering technique and integrated in a microfluidic channel. Probe-DNA immobilized on the fiber-coupler surface enables specific recognition of target DNA sequences and effectively facilitates the trapping of target DNA molecules. The binding characteristics of biomolecules on the fiber-coupler surface have been theoretically analyzed and experimentally demonstrated. Experimental results indicate that the spectral response of the loop-shaped fiber coupler immobilized with probe DNA exhibits a red-shift with the trapping of the DNA biomolecules. The proposed microfluidic system possesses such desirable merits as simple structure, label-free method and high integration, which make it a promising candidate for applications in molecular biology and related bioengineering areas.     

锥形光纤在空间光通信耦合系统中的应用

为了提高自由空间光通信的接收端耦合效率,将锥形光纤应用于光耦合,依据BPM算法的仿真结果使用熔融拉锥法制备了满足低损传输条件的锥形光纤。在实验上研究了锥形光纤和双锥形光纤模场传输特性。通过静态空间光-光纤耦合实验,对比了多/单模熔接光纤和锥形光纤光耦合效率和传输效率的差异,并研究了以上两种光纤结构耦合效率的横向偏移量容差。结果表明,锥形光纤的传输效率约为70%,具有低损传输特性、用于匹配后端单模光电子器件的良好滤波特性以及相比普通光纤更高的横向偏移量容差特性,因此可以广泛应用于自由空间光通信接收端光耦合、模式转换器等方面。