All-optical switching based on cascading of second-order nonlinearities in a periodically poled titanium-diffused lithium niobate waveguide

We report efficient all-optical switching by using a periodically poled titanium-diffused lithium niobate (Ti:PPLN) waveguide. The periodically domain inversion of the Ti:PPLN waveguide is achieved by electric field poling. The switching is driven by the second-order nonlinear effect of the cascading of phase-matched sum-frequency-generation and difference-frequency-generation processes. It is found that about 12% of the signal is switched by a 20-W gate power.