Influence of optical fiber positioning accuracy on IFU performance

The optical-fiber-based Integral Field Unit (IFU) is a very important device for astronomical observation. The IFU can obtain higher spatial resolution and good transmission efficiency. In this paper, a small IFU with 242 fibers was built for the prototype of the Fiber Arrayed Solar Optical Telescope (FASOT). It adopts the method of “micro lens + fiber array”. We designed the fiber with the core diameter of 35μm and NA 0.12. Two quartz positioning plates with micro pores were chosen to localize these fibers. And the micro lens was designed according to the parameter requirement. The coupling efficiency and the focal ratio between the micro lenses array and the fiber array are analyzed when position mismatch. The angular error is the main effect to influence the coupling efficiency.