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Chirped pulse amplification in a fiber optical parametric amplifier

Fiber optical parametric amplifiers (FOPAs) have attracted considerable attention during the last decade because of their broad bandwidth, high gain and wavelength-flexibility. In comparison to cumbersome bulky systems, they bring the advantages of all-fiber systems, i.e. reliability, long-term stability and compactness. FOPAs rely on the third-order susceptibility and are characterized by a quasi-instantaneous nonlinear response that involves pump, signal and idler waves. Chirped pulse amplification (CPA) allows to get a high energy amplification and its realization in FOPAs would increase the overall performances of these amplifiers. Such an experimental demonstration has never been reported in the past. In this work, we show for the first time the experimental feasibility of fiber-based optical parametric chirped pulse amplification (FOPCPA) with an all-fibered setup. The stretching/compression stages are realized with a single linearly chirped fiber Bragg grating (LCFBG) used in both directions while the amplification is performed in a CW-pumped FOPA that uses 500 meters of highly nonlinear fiber (HNLF). Fourier transform limited optical pulses at 1550 nm are stretched from 6 ps to 70 ps and then amplified by 22 dB without any spectral or temporal distortions. Experiments are confirmed by simulations carried out by numerical integration of the nonlinear Schrödinger equation with parameters matching those of the experimental setup. For simplicity, this first experimental demonstration is realized in the telecommunication window. By using photonic crystal fibers, one can move the working wavelength around 1 μm.