Yb:KYW crystal is an excellent laser gain material and are used as a lasing materials to generate ultrashort high power pulses. Yb:KYW can be used as ultrashort pulses amplifiers too. It is one of the best materials for high power thin disk lasers. Its broad spectral emission band 1023-1060nm allows the generation of ultrashort(80 -200 fs) high power pulses. Its wide absorption spectrum at 981 nm and high absorption of pump radiation allow an efficient use of diode laser pumping.Yb: KYW has the advantage of larger absorption cross section, which decreases the minimum pump intensity necessary to achieve transparency in the quasi-two-level system of ytterbium.