High-Average-Power Nanosecond Quasi-Phase-Matched Single-Pass Optical Parametric Generator in Periodically Poled Lithium Niobate

A pulsed nanosecond optical parametric generator (OPG) in periodically poled lithium niobate (PPLN) crystal is presented. The pump laser is an acousto-optically Q-switched Nd:YVO₄ laser with the maximum average power of 6.58W. When the repetition rate is 50kHz and the pulse width of the pump source is 80ns, the maximum average total output power of the single-pass PPLN OPG is about 1.9W, which includes 1.322W of 1.536μm signal radiation. The length of the PPLN crystal is only 38.7mm (at room temperature) with a grating period of 28.93μm (at room temperature). The 1.502--1.536μm signal radiation and 3.652--3.465μm idler radiation are obtained by adjusting the PPLN crystal temperature from 155°C to 250°C.