Abstract：Basic principles of ultra-stable lasers and Pound-Drever-Hall（PDH）method are introduced. Additionally, methods of reducing noises, such as noises from vibration, temperature perturbation, air turbulence and etc. are discussed. The applications of ultra-stable lasers, especially the application of ultra-stable lasers to achieve the ultra-stable microwave source are described. Finally, an ultra-stable laser system with parameters for an ultra-stable microwave source is presented.
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2013, Vol. 34 
