All-optical switching with low-peak power in microfabricated AlGaAswaveguides

We report all-optical switching with low-peak power in a microfabricated AlGaAs waveguide operating at 1.6 μm. We show that by using a 1-μm long microfabricated strongly-guided waveguide with 0.8 μm by 0.9 μm mode cross-sectional area, switching is achieved with an average power of 1.2 mW for 82-MHz mode-locked 430 fs pulses. The estimated peak pump power and pulse energy inside the microfabricated waveguide were ~30 W and ~14.6 pJ, respectively, which is 5-10 times lower than the values needed with conventional waveguides. In terms of a practicality index defined via switching power times waveguide length, this waveguide has around the best value