All-optical switching by use of cascading of phase-matched sum-frequency generation and difference-frequency generation processes

We have investigated proposed all-optical switching by use of cascading of phase-matched sum-frequency-generation (SFG) end difference-frequency-generation (DFG) processes. The switching operation is accomplished by both a rr phase change and an amplitude change of the signal field in SFG-DFG processes. We theoretically confirmed that the proposed switch requires the least operation power of any switch that uses cascading SFG-DFG processes. The switching characteristics have been numerically clarified, and the experiment al full-switching characteristics when a bulk-type periodically poled LiNbO3 is used correspond to the numerical analysis. An ultrafast all-optical switch with low switching power and small size can be expected from use of waveguide-type devices. (C) 1997 Optical Society of America [S0740-3224(97)04311-7].