This paper describes the tuning principle and the experimental technique of OPO.Temperature tuning curves of LiNbO

3

crystal OPO are calculated

and the experimental results of singly-resonant parametric LiNbO3 are shown.The tuning range of the signal wavelength was measured to be 1.3-2.0μm.The output energy at 1.9μm was 0.37mJ/pulse at 10pps.The device is a temperature tuned singly-resonant LiNbO3 OPO pumped by a Q-Switched 1.06μm Nd:YAG laser.The parametric oscillator cavity mirrors are designed for the transmittivity

T

≥90% at 1.06μm

and the reflectivity

R

≥97% at 1.3-2.0μm.The LiNbO3 crystal

with a length of and the phase matching angle 6 of 50°

was coated with an anti-reflective layer(

T

≥80% at 1.06-2.0μm).The crystal was mounted in the oven with the temperature controlling accuracy of ±0.05℃.The tuning range of the signal wavelength was measured to be 1.3-2.0μm and the corresponding temperature range of the LiNbO

3

crystal was 130°-250℃

The output energy at l

9μm was 0.37 mJ/pulse at 10pps