All-Optical Switching In Lithium Niobate Directional Couplers With Cascaded Nonlinearity

We report on intensity-dependent switching in lithium niobate directional couplers. Large nonlinear phase shifts that are due to cascading detune the coupling between the coupler branches, which makes all-optical switching possible. Depending on the input intensity, the output could be switched between the cross and the bar coupler branches with a switching ratio of 1:5 and a throughput of 80%. © 1996 Optical Society of America