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。
