Aluminum-free 980-nm GaInAs/GaInAsP/GaInP pump lasers

We report on the fabrication and characteristics of Al-free pump lasers for erbium-doped fiber amplifiers. Limitations of the two-dimensional passive waveguide approximation are discussed. With a closely optimized laser structure, a CW output power of 200 mW in the fundamental transverse mode was achieved. A slight change in "strength" of vertical mode confinement was shown to change significantly the onset of catastrophic optical damage of a mirror facet. Experimental observations for the longitudinal mode operation without mode jumps over a wide range of driving current are outlined. No mode jumps mere observed for long cavity lasers up to an output power level of 110 mW.<
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