A low density medium like a gas is attractive for laser amplification due to its high breakdown threshold and scalability to very large volumes. Moreover, the non-linear index of refraction of a gas is of three orders of magnitude lower than for a solid medium that is particularly suitable for direct amplification, without pulse stretching, of high-power ultrashort pulses. Among all gas laser media, application of the photolytical XeF(C-A) laser for high energy amplification is very attractive for the development of ultra-high power laser systems up to the petawatt power level due to the XeF(C-A) broad amplification bandwidth (80 nm FWHM centered near 475 nm) and a rather high saturation fluence (~0.05 J.cm-2), as well as a very low level of Amplified Spontaneous Emission. The paper presents the strategy of the LP3 laboratory to develop a high-contrast multiterawatt femtosecond laser chain based on a hybrid (solid/gas) technology, including a Ti:Sapphire oscillator generating 50 fs pulses at 950 nm, an Optical Parametric Chirped Pulse Amplification stage, a frequency converter, and a final high-energy amplification in the photolytical XeF(C-A) amplifier. Our approach is supported by first pilot experiments of femtosecond pulse amplification in a compact photolytical XeF(C-A) amplifier.