Picosecond Optical Pulse Generation Using Cascaded Mach-zehnder Electro-optic Light Intensity Modulators

In this paper, the author proposes a technique for the generation of picosecond optical pulses using cascaded Mach-Zehnder electrooptic light intensity modulators. Each individual Mach-Zehnder modulator is driven by the same microwave signal. By providing proper dc bias to the modulators, the repetition frequency of the generated optical pulse can be made equal to twice the frequency of the applied microwave drive signal. By tuning the microwave drive frequency, the repetition frequency of the generated optical pulse can be varied. The normalized optical pulse intensity and pulse width of the generated pulse have been calculated. The variation of the pulse width with different system parameters is also presented. Typical pulse width of 2.52 picosecond can be achieved using a cascade of four modulators driven by 60 GHz mm-wave signal.