Optical frequency intermodulation between two picosecond laser pulses

We present a method which transfers a nearly linear frequency modulation of bandwidth 3.5 THz (or 0.32 nm around 0.53 μm) to a frequency doubled single pulse of duration 30 ps emmited from a mode-locked laser. The experimental setup includes one stage to shape the pulses by a passive spectral filter, another to self-modulate their phase by nondispersive propagation through a single-mode optical fiber, and a final stage to multiply the pulse complex amplitudes in a harmonic-generating crystal. In practice, the proposed System is able to modulate subnanosecond laser pulses according to a wide variety of laws of temporal phase modulations.