The phase noises of a 10-m polarization-maintaining (PM) fiber and a 10-W PM fiber amplifier are experimentally measured. The results indicate that the 10-m PM ˉber with similar phase noise could be used to investigate the architecture of master oscillator power ampliˉer coherent combination. A seven-element hexagonal ˉber coherent array is developed to investigate the far-ˉeld distribution and phase controlling technique of a coherently combining ˉber laser array. A hexagonal prism is designed as the combining and splitting component to achieve a ˉll factor of 0.66. The hill climbing method is employed to detect and lock the element phase.