Design and experimental investigation of a 2.05µm single mode fiber coupler with high coupling efficiency

With the self focusing lenses, we design a 2.05μm single mode fiber coupler and calibrate the maximum value of coupling efficiency by experiment. The results show that the coupling efficiency could reach the maximum of 25.4%, which satisfy the requirement of receiving system of 2.05μm coherent wind lidar, thus realize miniaturization and all light transmitted by fiber of the receiving system. At last, the errors affecting the system are analyzed by semi-quantitative method.