This thesis will demonstrate how to setup the OPO system,and how to make a 2cm long 1D PPLN。 At first,the theory of nonlinear frequency conversion and quasi-phase matching is briefly introdueced. And then,several fabrication processes are introduced。We have already successfully fabricated 2cm 1D PPLN,and lasing the signal of OPO at our lab。 Final,optical measurements are listed。