Direct combining output of fiber coupled laser diodes via fiber combiner with high efficiency and multiple input ports

Abstract

Due to numerical aperture mismatch of cladding propagation mode with end cap, pump combiner can’t be used for direct combining output of fiber coupled laser diodes equipped with quartz block head (QBH). Herein, according to the theoretical analysis and careful selection of fibers, a 19 × 1 fiber combiner with multiple input ports and terminated with QBH for direct combining output of fiber coupled laser diodes is fabricated successfully in experiment. The minimal thermal load of fiber combiner under high power circumstances is necessary for long term and stable operation. The combiner is capable of handling a combined output power of 3125 W with transmission efficiency higher than 98.6 % and a maximum temperature of 28.6℃, indicating excellent thermal management. The details of making such a fiber component are presented, which are expected to have a positive instruction on corresponding fiber device fabrication.