Summary form only given. Efficient, diode-pumped high energy femtosecond laser systems around 1 μm based on Yb-gain media are readily commercially available. However, owing to the gain bandwidth limitations, the pulses generated in such lasers are substantially longer than the ones generated in Ti:Sapphire systems. A simple, energy-scalable pulse self-compression scheme for the pulses around 1 μm thus would be of great interest for many applications, including time-resolved pump-probe spectroscopy, high-harmonics generation, etc. The self-phase modulation during nonlinear propagation in filaments in gasses is often employed for pulse self-compression. Such schemes typically require rather bulky setups and careful control of group velocity dispersion. Some years ago it has been shown theoretically that Raman-active molecules in gaseous form could be used for mid-infrared pulse compression. Here we exploit highly-efficient interaction of optical pulses with phonon-polaritons in KTi0PO4 (KTP) for self -compression of fs pulses at 1 gm. The experimental setup consists of a 1030 nm femtosecond pump laser. The pulses were loosely focused by a f=150 mm lens to a beam waist with 1/e 2 radius of 160 gm in a 10 mm -long, 5mm-thick single -domain KTP sample. The pulses were polarized along the c -axis of the crystal. The dependence of the pulse output spectrum as a function of the beam focus position in the crystal is shown, where 300 fs full width at half maximum (FWHIVI) input pulses from a fiber -based system were employed. The broadest spectrum was obtained with the focal plane being located close to the entrance of the crystal. We employed time resolved digital holography to verify the coupling of the optical pulse with phonon-polariton wave during propagation through the crystal. Characterization experiments with 173 fs FWIINI pulses derived from a commercial solid-state laser system were conducted using a custom-built d -scan setup [6]. The setup included chirped mirror...