Instabilities in laser-plasma interaction (LPI) are the main barriers to achieving laser ignition successfully.Spike trains of uneven duration or delay (STUD)pulses[1] have been shown to possess great potential in controlling the nonlinear increase of instability of LPI.In an STUD,the multi-nanosecond laser pulses are broken up into a series of uncorrelated spikes on the pico-second time scale with intentional variation of the amplitude and duration.Traditionally,generation of an optical pulse train is ordinarily used with Q-switching and mode locking of wide-band lasers.[2-4] The pulse width depends strongly on the laser linewidth and the repetition rate is limited by the cavity length.Thus,the pulses from these lasers have limited adjustable temporal characteristics in the pulse width,repetition rate,and shape.Hence,these methods are limited in generation of STUD pulscs.On the other hand,direct generation of optical pulse by electro-optic (EO) modulation technique has been explored alteatively.[5-15] These techniquesown a big freedom to adjust the pulse shape,width,and repetition rate,which is applicable to all kinds of lasers,regardless of the linewidth.An EO switch can chop a continuous-wave laser into a short pulse with arbitrary repetition rate;however,the pulse width is limited by the responsive bandwidth of the switch.[5]A much shorter pulse can be generated by using the time lens technique.[5-9] In this device,a pulse is imposed on a temporal quadratic phase profile with the desired bandwidth by the exteal electro-optic modulation,and then de-chirped and compressed by the grating pair.The repetition rate and the temporal width of the output pulses are determined entirely by the driving frequency and the modulation strength.