Mode-locking of high power lasers by a combination of intensity and time dependent Q-switching

A new method for simultaneous mode-looking and Q-switching of high power lasers by a combination of intensity and time dependent Q-switching is described. The two Q-switching mechanisms are achieved by equipping the laser with a device, here called the “Electro-Opto-Optical Modulator” (EOOM). The modulator, which is driven by the optical field which it modulates in addition to an external electric field, contains nonlinear media which exhibit a large optical as well as dc Kerr effect. The advantages of this combined Q-switching compared with a pure intensity dependent Q-switching are that the generation of the model-locked pulses can be predetermined in time and that the length of the Kerr active medium can be decreased.