Optical parametric oscillator performance at high average power

Summary form only given. While there has been considerable success in efficiently generating mid-IR radiation with potassium titanyl phosphate (KTP), here we investigate a critically phased-match optical parametric oscillator (OPO) pumped at high average power (>100 W) to generate output in the 1.555-/spl mu/m atmospheric window. Given the strong absorption of KTP at the idler wavelength (3.37 /spl mu/m), this results in a significant thermal load to the crystal and hence a significant optical aberration. The degradation in OPO performance at high energy per pulse and high average power operation is investigated numerically.