980-nm master oscillator power amplifiers with nonabsorbing mirrors

High-power master oscillator power amplifiers with nonabsorbing mirrors have been fabricated. These devices exhibit 1.0 and 1.5 W of single-frequency diffraction-limited continuous-wave optical powers at relatively low-amplifier currents of 1.75 and 2.6 A, respectively. These devices operate with a single longitudinal mode with a 40-dB sidemode suppression ratio over the entire amplifier current range without any longitudinal mode hops as a result of the very low optical feedback from the PA facet. Coupling of over 500 mW into a single-mode fiber is also achieved.