Novel design of wedge-shaped lensed fibers for fiber-laser coupling by using a wide-angle beam propagation method

摘要

The non-Gaussian mode modification effect caused by a wedged tip is analyzed in details by using a precise three-dimensional wide-angle beam propagation method (WA-BPM) to design the wedge-shaped lensed fibers for coupling between laser diodes of highly asymmetrical beam and single-mode fibers. In comparison with the Fresnel reflection, the non-Gaussian mode modification effect is demonstrated to be the dominant factor in causing coupling loss and sharply reduces the coupling efficiency when the wedge angle grows beyond one certain value. Based on the study, an effective and easy-to-fabricate modified wedged tip design is proposed to improve the coupling efficiency by reducing the non-Gaussian mode shape modification effect.