We have developed a 1.5-μm high-power laser amplifier using Er, Yb:glass planar waveguide for a coherent Doppler LIDAR. Large cooling surface of the waveguide realized highaverage power pumping for Er, Yb:glass which has low thermal fracture limit. Multi-bounce optical path configuration and high-intensity pumping provide high-gain operation in spite of small stimulated emission cross section. With pulsed operation, the maximum amplified signal power was 7.6-W with the amplified gain of more than 20 dB. The pulse energy of 1.9-mJ was achieved at the repetition rate of 4-kHz.