High-power 980-nm pump laser modules for erbium-doped fiber amplifiers

High-power fiber-coupled pump modules with an emission wavelength of 980 nm and output powers in excess of 200 mW, as measured at the fiber end, have been fabricated. Laser-to-fiber coupling efficiencies in excess of 77% are observed to be in excellent agreement with a mathematical model. Also, the output power stability of these modules has been monitored during severe temperature cycling, and the relative power variation was less than 4% for all the tested modules.