The proposed amplifier can be used for narrow linewidth CW and pulse amplification in ns/us regime due to the high SBS-threshold threshold. The proposed narrow linewidth pulsed fiber lasers in MOPA can be used for high resolution laser spectroscopy, velocimetry, anemometry, coherent Lidar, imagery, laser frequency conversion, and ranging finding owing to their high spatial and spectral qualities. NASA's Goddard Space Flight Center, Langley research center, and Ames Research Center have been investigating a number of remote sensing concepts using fiber lasers. For example, they are developing the fiber laser spectroscopic instruments for absorption lines of oxygen in the range of 760-770 nm to determine atmospheric pressure and temperature from their effect on the shape and strength of the A band absorption lines. The proposed high SBS-threshold high power amplifiers result in high power narrow linewidth pulsed fiber laser transmitter at 765 nm that is ideal source for NASA's fiber laser spectroscopic instruments from ground, airborne, and space-based platform. Also, it can be used in other planned missions or technology programs, such as Doppler Wind Lidar, Lidar for Surface Topagraphy (LIST), and Earth and Planetary Atmospheric Composition (ASCENDS).planned missions or technology programs, such as Doppler Wind Lidar, Lidar for Surface Topagraphy (LIST), and Earth and Planetary Atmospheric Composition (ASCENDS).