electro optical modulator is comprised of a device 2 capable rotating polarization of a beam inside the cavity polarizer 3 and optionally a lambda plate 6 said cavity can further include more optical components 7 such as kerr lens mode locking unit dispersion and diffraction compensating optics etalons etc said electro optical device 2 is controlled by means of an electronics unit 8 in this context an electro optical device 2 is any optical unit capable of changing the polarization state of an incident beam upon actuation by a control signal said optical unit can be controlled by application of electric and or magnetic field once an electric control signal is switched on the type and configuration of the electro optical element should not be considered as limiting as far as the unit is capable of changing the polarization state of an incident laser beam or modulate the beam by means of periodic or non periodic changes in polarization the polarizer 3 can be of any type as long as beams of s and p polarizations are separated into two separate pathways i e it can be a thin film polarizer polarizing cube nicol wollaston prisms or any other used by those skilled in the art in the most preferred embodiment the electro optical unit is controlled by means of electrical signal having a specific waveform as shown in fig1 and fig2 a 2b the waveform comprises essentially switching between the voltage u open and the bias voltage u closed with oscillations appearing at one of the states at which conditions for amplification of a light pulse are ensured in this example it is u closed there are several ways of arranging the pockels cell 2 inside the cavity it can be.