Fig. 1. Pump light with different NAs transmitting in the (2 + 1) × 1 side pumping combiner.

Fig. 2. Transmission paths of pump light with different NAs in the combiner calculated through the geometric method.

Fig. 3. (a) Schematic diagram of the manufacturing system of the combiner, insert: a side microscope picture of the manufactured side pump combiner; (b) the physical picture of a combiner packaged in copper fixture.

Fig. 4. Scanning diagrams of fusion areas of different side pumping combiner samples; (a), (b) represent the fabrication parameters of combiners designed for LD pumping and YDFL pumping, respectively.

Fig. 5. Experimental setup of the coupling efficiency and temperature characteristic testing system of combiner 1 (with LD pumping).

Fig. 6. Results of pump coupling efficiency and temperature characteristics of combiner 1 when pumped with the LD. Insert: the thermal picture of the home-made side pumping combiner when injecting 2267 W LD pump power.

Fig. 7. Experimental setup of the coupling efficiency and temperature characteristic testing system of combiner 3 (with YDFL pumping).

Fig. 8. Results of pump coupling efficiency and temperature characteristics of combiner 3 when pumped with the YDFL. Insert: the thermal picture of the home-made side pumping combiner when injecting 2730 W YDFL pump power.