Optical frequency synthesis based on mode-locked lasers

The synthesis of optical frequencies from the primary cesium microwave stan dard has traditionally been a difficult problem due to the large disparity in frequency. Recently this field has been dramatically advanced by the int roduction and use of mode-locked lasers. This application of mode-locked la sers has been particularly aided by the ability to generate mode-locked spe ctra that span an octave. This review article describes how mode-locked las ers are used for optical frequency synthesis and gives recent results obtai ned using them. (C) 2001 American Institute of Physics.