High-power monolithically integrated flared amplifier master oscillator power amplifiers (MFA-MOPA's) have been fabricated that operate up to 2 W continuous wave in a single diffraction-limited lobe. The spectral output of the MFA-MOPA is single longitudinal mode with a side-mode suppression ratio greater than 25 dB. Several operating characteristics of the MFA-MOPA, including the beam astigmatism, amplifier gain saturation, linewidth, far-field extinction ratio, and beam quality metrics, are investigated and discussed.