Abstract

High-repetition-rate optical frequency-comb sources emitting picosecond pulses play an important role in various scientific areas and industrial applications. Such ultrafast pulse sources are mostly generated in optical cavities or microresonators. By means of the wavelength-conversion techniques, it is then possible to transfer such robust and compact near-IR sources from the visible to the mid-IR wavelength regions [1-3], for which there exists an increasing demand, for biophotonics and other applications. Here we demonstrate the generation of high-repetition-rate picosecond pulses in the visible wavelength range by using an optical cavity-less configuration. To this aim, we first developed a tunable C-band picosecond pulse generator at a repetition-rate of 40 GHz. This near-IR optical cavity-less system makes use of highly reliable components developed for optical communications [4]. Next, it was used to directly pump a nonlinear periodically poled ridge LiNbO₃ (PPLN) waveguide fabricated on silicon substrate [5].

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