**4. Conclusion**

In a conclusion, the SA algorithm is employed to design nonlinear frequency conversion devices. The basic design method is explained in detail. Some devices include multiple second harmonics generation devices, multiple coupled third harmonics generation devices, multiple channeled photonic crystal filters, multiple second harmonics photonic crystal devices, and multiple coupled third harmonics photonic crystal devices are designed using the proposed method. The designed devices can achieved preset goals well. It is expected that this new proposed method can provide a novel approach for nonlinear conversion devices design.
