Efficient 521 nm all-fiber laser: splicing Pr^3+-doped ZBLAN fiber to end-coated silica fiber

We demonstrated a green all-fiber laser by splicing both ends of a Pr(3+)-doped ZBLAN fiber to silica fibers, whose ends were coated with a dielectric thin film. The output power and the slope efficiency were 322 mW and 53%, respectively, and the coupled pump power of the two blue GaN pump lasers in the silica fiber core was 652 mW. We estimated that the damage threshold of the spliced structure was at least 21 MW/cm². This splicing technique should be applicable for other wavelengths and glass fibers having low melting temperatures.