MgO:LiNbO3 crystal is widely used for high power frequency doubling(SHG), mixing(SFG) and optical parameter oscillator(OPO). MgO:LiNbO3 has similar effective nonlinear coefficients as pure LiNbO3. But it has the advantages such as high damage threshold (over 5 GW/cm2 @ 1064 nm, 12ns), noncritical phase matching (NCPM) at room temperature, excellent E-O and NLO properties, good mechanical and chemical properties compared with pure LiNbO3. Over 45% and 60% of SHG efficient are obtained in pulsed and cw Nd:YAG lasers respectively, by angle tuned phase matchable SHG of Nd:YAG laser (1064 nm) and NCPM SHG of laser lasers (1053 nm) of MgO:LiNbO3 at room temperature. MgO:LiNbO3 is also a good crystal for high power quasi-phase-matched waveguide structure for doubler, optical parametric oscillator (OPO) and amplifier (OPA). Jingsheng optoelectronics supplies the typical sizes of MgO:LiNbO3 crystals - 5x5x(20-30) mm3 for OPO and frequency doubler, (20-25)x(20-25)x1 mm3 for waveguide substrates. Other sizes and AR or HR-coatings are available upon request