Analysis of optimum coupling efficiency between random light and single-mode fiber

摘要

By assuming that the light coupled into a single-mode fiber is monochromatic generated by the diffused far field , employing the lens coupling theory and van Cittert-Zernike theorem, we obtain the general expressions of the coupling efficiency of an optical fiber. This subject focuses on the analysis that the incident light is plane wave; we obtain the F number of coupling lens, which provides the theory support for the design of the coupling lens, corresponding to the optimum coupling efficiency. Fiber coupling efficiency is not only related to the mode matching of incident light and the fiber; the optical axis, the symmetrical axis of lens and the fiber center line misalignment also affect. Simulation results of misalignment errors show that the defocus alignment has little effect on the coupling efficiency, while the effect of both lateral alignment error and angle offset on the coupling efficiency is relatively large.