通过改进光纤定向耦合器的结构,可以显著提高光纤速度干涉仪的灵敏度。该文从熔融拉锥型光纤定向 耦合器的数学模型出发进行研究,详细分析了2 2和3 3型光纤定向耦合器在全光纤速度干涉仪(AFVISAR)中的 具体作用,并对此两种结构的光纤速度干涉仪的性能(主要是灵敏度)的优劣进行了对比分析,表现出3 3型光纤定向耦 合器构成的两端探测系统的优越性。最后提出采用N N型光纤定向耦合器可能带来的光纤速度干涉仪性能的提高和适用 局限性。

The sensitivity of an optical fiber velocity interferometer can be improved by modifing the structure of an optical fiber directional coupler. In this paper, the mathematical model of a melting optical fiber directional coupler is studied. The specific functions of the 2 2 and 3 3 optical fiber directional couplers in All Fiber Velocity Interferometers (AFVISAR) are analyzed in detail. Those two different AFVISARs are compared with each other in performance. The result shows that the two-end detection system based on a 3 3 optical fiber directional coupler is better. Finally, the potential performance improvement of an AFVISAR to be achieved by using a N N optical fiber directional coupler is proposed.