Frequency-stabilized 1 W optical comb at 2.2-2.6 um by Cr2+:ZnSe multipass amplification

We present a frequency comb source with power level up to 150 ?W per comb mode, tunable in the 2.2-2.6 ?m wavelength region, based on a Cr(2+):ZnSe multipass solid-state amplifier seeded by the output of an actively stabilized optical parametric oscillator, synchronously pumped by a commercial 250 MHz Er:fiber laser. Phase relationship between idler, signal, and pump waves is exploited to perform frequency comb stabilization in the whole 2.2-2.6 ?m mid-infrared spectral region.