All-optical 2 * 2 switching with two independent Yb3+-doped nonlinear optical fibers with a long-period fiber grating pair

We have demonstrated a new type of all-optical 2*2 switch by using two independent Yb3+-doped nonlinear optical fibers with a long-period fiber grating pair and a 3-dB fiber coupler. A 400-Hz square-wave pulse train at ~1549.4 nm was fully switched between the two output ports up to 200 Hz by modulated pump signals at 976 nm with a maximum pump power of ~35 mW, where the extinction ratio at ~1549.4 nm between the on and the off states was ~17.5 dB.