Improving the power and efficiency of 9xx-nm broad-area laser diodes has a great help in reducing the cost of laser systems and expanding applications. This letter presents an optimized epitaxial structure with high power and conversion efficiency. Laser diodes with 230 mu m emitter width and 5 mm cavity length deliver continuous-wave output power up to 48.5 W at 48 A, 30 degrees C, the highest power reported for 9xx-nm single emitter lasers so far. The slope efficiency is as high as 1.23 W/A due to a low internal optical loss of 031 cm(-1) and a high internal efficiency of 96%. The maximum power conversion efficiency reaches 72.6% at 153 W and 67.3% at the operating power of 30 W under a heatsink temperature of 25 degrees C. Life test results show no failure in 1000 hours for 55 laser diodes.